Optical integrating chamber lighting using multiple color sources

ABSTRACT

A system to provide radiant energy of selectable spectral characteristic (e.g. a selectable color combination of light) uses an optical integrating cavity to combine energy of different wavelengths from different sources. Sources of radiant energy of different wavelengths, typically different-color LEDs, supply radiant energy into the interior of the cavity. The cavity has a diffusely reflective interior surface and an aperture for allowing emission of combined radiant energy. Control of the intensity of emission of the sources sets the amount of each wavelength of energy in the combined output and thus determines a spectral characteristic of the radiant energy output through the aperture. A variety of different elements may optically process the combined light output, such a deflector, a variable iris, a lens, a variable focusing lens system, a collimator, a holographic diffuser and combinations thereof. Such systems are useful in various luminous applications as well as various illumination applications.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part and claims the benefit of thefiling date of U.S. patent application Ser. No. 10/601,101, filed Jun.23, 2003, entitled “Integrating Chamber Cone Light Using LED Sources,”the disclosure of which is entirely incorporated herein by reference.

TECHNICAL FIELD

The present subject matter relates to techniques and equipment toprovide radiant energy having a selectable spectral characteristic (e.g.a selectable color characteristic), by combining selected amounts ofradiant energy of different wavelengths from different sources, using anoptical cavity.

BACKGROUND

An increasing variety of lighting applications require a preciselycontrolled spectral characteristic of the radiant energy. It has longbeen known that combining the light of one color with the light ofanother color creates a third color. For example, the commonly usedprimary colors Red, Green and Blue of different amounts can be combinedto produce almost any color in the visible spectrum. Adjustment of theamount of each primary color enables adjustment of the spectralproperties of the combined light stream. Recent developments forselectable color systems have utilized light emitting diodes as thesources of the different light colors.

Light emitting diodes (LEDs) were originally developed to providevisible indicators and information displays. For such luminanceapplications, the LEDs emitted relatively low power. However, in recentyears, improved LEDs have become available that produce relatively highintensities of output light. These higher power LEDs, for example, havebeen used in arrays for traffic lights. Today, LEDs are available inalmost any color in the color spectrum.

Systems are known which combine controlled amounts of projected lightfrom at least two LEDs of different primary colors. Attention isdirected, for example, to U.S. Pat. Nos. 6,459,919, 6,166,496 and6,150,774. Typically, such systems have relied on using pulse-widthmodulation or other modulation of the LED driver signals to adjust theintensity of each LED color output. The modulation requires complexcircuitry to implement. Also, such prior systems have relied on directradiation or illumination from the individual source LEDs. In someapplications, the LEDs may represent undesirably bright sources ifviewed directly. Also, the direct illumination from LEDs providingmultiple colors of light has not provided optimum combination throughoutthe field of illumination. In some systems, the observer can see theseparate red, green and blue lights from the LEDs at short distancesfrom the fixture, even if the LEDs are covered by a translucentdiffuser. Integration of colors by the eye becomes effective only atlonger distances.

Another problem arises from long-term use of LED type light sources. Asthe LEDs age, the output intensity for a given input level of the LEDdrive current decreases. As a result, it may be necessary to increasepower to an LED to maintain a desired output level. This increases powerconsumption. In some cases, the circuitry may not be able to provideenough light to maintain the desired light output level. As performanceof the LEDs of different colors declines differently with age (e.g. dueto differences in usage), it may be difficult to maintain desiredrelative output levels and therefore difficult to maintain the desiredspectral characteristics of the combined output. The output levels ofLEDs also vary with actual temperature (thermal) that may be caused bydifference in ambient conditions or different operational heating and/orcooling of different LEDs. Temperature induced changes in performancecause changes in the spectrum of light output.

Another problem with existing multi-color LED systems arises fromcontrol of the overall system output intensity. In existing systems, toadjust the combined output intensity, e.g. to reduce or increase overallbrightness, the user must adjust the LED power levels. However, LEDspectral characteristics change with changes in power level. If thelight colors produced by the LEDs change, due to a power leveladjustment, it becomes necessary to adjust the modulations to compensatein order to achieve the same spectral characteristic.

U.S. Pat. No. 6,007,225 to Ramer et al. (Assigned to Advanced OpticalTechnologies, L.L.C.) discloses a directed lighting system utilizing aconical light deflector. At least a portion of the interior surface ofthe conical deflector has a specular reflectivity. In several disclosedembodiments, the source is coupled to an optical integrating cavity; andan outlet aperture is coupled to the narrow end of the conical lightdeflector. This patented lighting system provides relatively uniformlight intensity and efficient distribution of light over a field ofillumination defined by the angle and distal edge of the deflector.However, this patent does not discuss particular color combinations oreffects.

Hence, a need still exists for a technique to efficiently combine energyfrom multiple sources having multiple wavelengths and direct the radiantenergy effectively toward a desired field of illumination. A relatedneed still exists for such a system that does not require complexelectronics (e.g. modulation circuitry) to control the intensity of theenergy output from the sources of the radiant energy of differentwavelengths. A need also exists for a technique to effectively maintaina desired energy output level and the desired spectral character of thecombined output as LED performance decreases with age, preferablywithout requiring excessive power levels.

SUMMARY

As disclosed herein, an apparatus for emitting radiant energy includesan optical cavity, having a diffusely reflective interior surface and anaperture for allowing emission of combined radiant energy. Sourcessupply radiant energy into the interior of the cavity. At least two ofthe sources emit radiant energy of different wavelengths. The cavityeffectively combines the energy of the different wavelengths, so thatthe radiant energy emitted through the aperture includes the radiantenergy of the various wavelengths. The apparatus also includes anoptical processing element coupled to the aperture of the opticalcavity.

A variety of different optical processing elements are disclosed.Individual examples may be selected or two or more such elements may beused in combination, to facilitate use of the apparatus for a particularluminance or illumination application. Disclosed examples of the opticalprocessing element include deflectors of various shapes and reflectivecharacteristics, collimators, various lenses, focusing systems, irises,diffusers, holographic diffusers and the like.

A system using an apparatus as disclosed herein will include a controlcircuit, coupled to the sources for establishing output intensity ofradiant energy of each of the sources. Control of the intensity ofemission of the sources sets a spectral characteristic of the combinedradiant energy emitted through the aperture. If the fixture includes avariable iris, the output intensity may be adjusted by adjustment of theiris opening without the need to change the power levels of the sources,and thus without impact on the spectral characteristic of the output.

In the examples, the points of entry of the energy from the sources intothe cavity are located so that the emission points are not directlyvisible through the aperture. Each source typically comprises one ormore light emitting diodes (LEDs). It is possible to install anydesirable number of LEDs. Hence, In several examples, the sources maycomprise one or more LEDs for emitting light of a first color, and oneor more LEDs for emitting light of a second color, wherein the secondcolor is different from the first color. In a similar fashion, theapparatus may include additional LED sources of a third color, a fourthcolor, etc. To achieve the highest color-rendering index (CRI), the LEDarray may include LEDs of colors that effectively cover the entirevisible spectrum.

The sources can include any color or wavelength, but typically includered, green, and blue. The integrating or mixing capability of theoptical cavity serves to project light of any color, including whitelight, by adjusting the intensity of the various sources coupled to thecavity. Hence, it is possible to control color rendering index, as wellas color temperature. The system works with the totality of light outputfrom a family of LEDs. However, to provide color adjustment orvariability, it is not necessary to control the output of individualLEDs, except as the intensity of each contributes to the totality. Forexample, it is not necessary to modulate the LED outputs. Also, thedistribution pattern of the LEDs is not significant. The LEDs can bearranged in any manner to supply radiant energy within the opticalcavity, although typically direct view from outside the fixture isavoided.

Other examples are disclosed which include one or more white lightsources. The white light source may be one or more white LEDs.Alternatively, such fixtures may utilize other light sources or lamps,such as incandescent or fluorescent light bulbs. In fixtures utilizingwhite light sources, the light from the colored LEDs provides anadjustment or correction to the white light output of the apparatus.

An exemplary system includes a number of “sleeper” LEDs that would beactivated only when needed, for example, to maintain the light output,color, color temperature or thermal temperature. Hence, examples arealso disclosed in which the first color LEDs comprise one or moreinitially active LEDs for emitting light of the first color and one ormore initially inactive LEDs for emitting light of the first color on anas needed basis. Similarly, the second color LEDs include one or moreinitially active LEDs for emitting light of the second color and one ormore initially inactive LEDs for emitting light of the second color onan as needed basis. In a similar fashion, the apparatus may includeadditional active and inactive LED sources of a third color, fourthcolor, etc. or active and inactive LED sources of white light.

As noted in the background, as LEDs age or experience increases inthermal temperature, they continue to operate, but at a reduced outputlevel. The use of the sleeper LEDs greatly extends the lifecycle of thefixtures. Activating a sleeper (previously inactive) LED, for example,provides compensation for the decrease in output of the originallyactive LED. There is also more flexibility in the range of intensitiesthat the fixtures may provide.

A number of different examples of control circuits are discussed below.In one example, the control circuitry comprises a color sensor coupledto detect color distribution in the combined radiant energy. Associatedlogic circuitry, responsive to the detected color distribution, controlsthe output intensity of the various LEDs, so as to provide a desiredcolor distribution in the integrated radiant energy. In an example usingsleeper LEDs, the logic circuitry is responsive to the detected colordistribution to selectively activate the inactive light emitting diodesas needed, to maintain the desired color distribution in the combinedradiant energy.

A number of other control circuit features also are disclosed. Forexample, the control circuitry may also include a temperature sensor. Insuch an example, the logic circuitry is also responsive to the sensedtemperature, e.g. to reduce intensity of the source outputs tocompensate for temperature increases.

The control circuitry may include an appropriate device for manuallysetting the desired spectral characteristic, for example, one or morevariable resistors or one or more dip switches, to allow a user todefine or select the desired color distribution.

Automatic controls also are envisioned. For example, the controlcircuitry may include a data interface coupled to the logic circuitry,for receiving data defining the desired color distribution. Such aninterface would allow input of control data from a separate or evenremote device, such as a personal computer, personal digital assistantor the like. A number of the devices, with such data interfaces, may becontrolled from a common central location or device.

The control may be somewhat static, e.g. set the desired color referenceindex or desired color temperature and the overall intensity and leavethe device set-up in that manner for an indefinite period. The apparatusalso may be controlled dynamically, for example, to vary the color ofthe combined light output and thereby provide special effects lighting.Where a number of the devices are arranged in a large two-dimensionalarray, dynamic control of color and intensity of each unit could evenprovide a video display capability, for example, for use as a“jumbo-tron” view screen in a stadium or the like. In product lightingor in personnel lighting (for studio or theater work), the lighting canbe adjusted for each product or person that is illuminated. Also, suchlight settings are easily recorded and reused at a later time or even ata different location using a different system.

The disclosed apparatus may use a variety of different structures orarrangements for the optical integrating cavity. It is desirable thatthe interior cavity surface have a highly efficient diffusely reflectivecharacteristic, e.g. a reflectivity of over 90%, with respect to therelevant wavelengths. In several examples, the cavity is formed of adiffusely reflective plastic material, such as a polypropylene having a98% reflectivity and a diffuse reflective characteristic. Anotherexample of a material with a suitable reflectivity is SPECTRALON.Alternatively, the optical integrating cavity may comprise a rigidsubstrate having an interior surface, and a diffusely reflective coatinglayer formed on the interior surface of the substrate so as to providethe diffusely reflective interior surface of the optical integratingcavity.

A variety of different shapes may be used for the interior reflectivesurface of the cavity. Although it may be triangular or in the shape ofa pyramid, in several examples, the diffusely reflective interiorsurface of the optical integrating cavity has a shape corresponding to asubstantial portion of a sphere (e.g. hemispherical) or a substantialportion of a cylinder (e.g. approximating a half-cylinder). Otherexamples utilize an extended volume having a rectangular cross-section.

To provide a particular desirable output distribution from theapparatus, it is also possible to construct the cavity so as to provideconstructive occlusion. Constructive Occlusion type transducer systemsutilize an electrical/optical transducer optically coupled to an activearea of the system, typically the aperture of a cavity or an effectiveaperture formed by a reflection of the cavity. The systems utilizediffusely reflective surfaces, such that the active area exhibits asubstantially Lambertian characteristic. A mask occludes a portion ofthe active area of the system, in the examples, the aperture of thecavity or the effective aperture formed by the cavity reflection, insuch a manner as to achieve a desired response or output characteristicfor the system. In examples of the present apparatus using constructiveocclusion, the optical integrating cavity would include a base, a maskand a cavity formed in the base or the mask. The mask would have adiffusely reflective surface. The mask is sized and positioned relativeto the active area of the system so as to constructively occlude theactive area.

In one example of the present apparatus using constructive occlusion,the device would further include a mask outside the optical integratingcavity formed in the base. The mask would have a diffusely reflectivesurface facing toward the aperture of the cavity. The mask is sized andpositioned relative to the aperture so as to constructively occlude theaperture. In another constructive occlusion example, the aperture thatserves as the active area is actually a reflection of the interiorsurface of a dome that forms the curved interior of the cavity. Thereflection is formed on a base surface opposite the cavity of the dome.The interior of the cavity is diffusely reflective. In this laterarrangement, the dome also serves as the constructive occlusion mask.

The inventive devices have numerous applications, and the outputintensity and spectral characteristic may be tailored and/or adjusted tosuit the particular application. For example, the intensity of theintegrated radiant energy emitted through the aperture may be at a levelfor use in a lumination application or at a level sufficient for a tasklighting application. Exemplary luminance lighting systems providesymbol, letter number or character display lighting, for example, forsignage. Theater or studio lighting and product display lightingexamples are also disclosed.

A lighting system, for providing variable color lighting for studio ortheater applications, includes first and second sources of light offirst and second wavelengths. An optical cavity with a diffuselyreflective interior surface receives and combines light of the twowavelengths from the sources. The cavity also has an aperture, forallowing emission of combined light of both wavelengths. The lightingsystem also includes a variable opening iris optically coupled to theaperture of the optical cavity, for controlling an amount of thecombined light emitted from the aperture directed toward a subject to beilluminated. Control circuitry, coupled to the second sources,establishes intensity of light from the sources, so as to set a spectralcharacteristic of the combined light directed toward the subject to beilluminated in the studio or theater.

In a theater or studio lighting system of this type, the control of thesources controls the spectral characteristic of the emitted light. Asdisclosed, adjustment of the size of the opening through the iris inturn controls the intensity of the overall system light output.Disclosed examples of such a system include one or more additionaloptical processing elements, such as a variable focusing lens system tocontrol the size of the spot illuminated onto the subject.

A lighting fixture, for a luminous lighting application, includes lightsources for supplying light of two different wavelengths. Again, anoptical cavity with a diffusely reflective interior surface receives andcombines light of the different wavelengths, and an aperture of thecavity allows emission of the combined light. This luminous fixtureincludes at least one optical processing element coupled to the apertureof the optical cavity, for processing the combined light in a mannerfacilitating the luminous lighting application.

In addition to the examples of the optical processing elements mentionedearlier, the examples for the luminous fixture include deflectors shapedlike numbers, characters, letters, or other symbols. In such fixtures,the apertures may be similarly shaped. By contouring and combining suchfixtures, it is possible to spell out words and phrases lighted inaccord with the principles described herein.

Additional objects, advantages and novel features of the examples willbe set forth in part in the description which follows, and in part willbecome apparent to those skilled in the art upon examination of thefollowing and the accompanying drawings or may be learned by productionor operation of the examples. The objects and advantages of the presentsubject matter may be realized and attained by means of themethodologies, instrumentalities and combinations particularly pointedout in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations in accord withthe present concepts, by way of example only, not by way of limitations.In the figures, like reference numerals refer to the same or similarelements.

FIG. 1 illustrates an example of a radiant energy emitting system, withcertain elements thereof shown in cross-section.

FIG. 2A is an exploded side-view of the components of a fixture usableas the cavity, deflector and sources, in the system of FIG. 1.

FIG. 2B is an exploded view of the components of FIG. 2A, with severalof those components shown in cross-section.

FIG. 2C is an end view of the deflector.

FIG. 2D is an end view of the cavity assembly.

FIG. 2E is a plan view of the LED support ring.

FIG. 3 illustrates another example of a radiant energy emitting system,with certain elements thereof shown in cross-section.

FIG. 4 is a bottom view of the fixture in the system of FIG. 3.

FIG. 5 illustrates another example of a radiant energy emitting system,using fiber optic links from the LEDs to the optical integrating cavity.

FIG. 6 illustrates another example of a radiant energy emitting system,utilizing principles of constructive occlusion.

FIG. 7 is a bottom view of the fixture in the system of FIG. 6.

FIG. 8 illustrates an alternate example of a radiant energy emittingsystem, utilizing principles of constructive occlusion.

FIG. 9 is a top plan view of the fixture in the system of FIG. 8.

FIG. 10 is a functional block diagram of the electrical components, ofone of the radiant energy emitting systems, using programmable digitalcontrol logic.

FIG. 11 is a circuit diagram showing the electrical components, of oneof the radiant energy emitting systems, using analog control circuitry.

FIG. 12 is a diagram, illustrating a number of radiant energy emittingsystems with common control from a master control unit.

FIG. 13 is a layout diagram, useful in explaining an arrangement of anumber of the fixtures of the system of FIG. 12.

FIG. 14 depicts the emission openings of a number of the fixtures,arranged in a two-dimensional array.

FIGS. 15A to 15C are cross-sectional views of additional examples, ofoptical cavity LED light fixtures, with several alternative elements forprocessing of the combined light emerging from the cavity.

FIG. 16 is a cross-sectional view of another example of an opticalcavity LED light fixture, using a collimator, iris and adjustablefocusing system to process the combined light output.

FIG. 17 is a cross-sectional view of another example of an opticalcavity LED light fixture.

FIG. 18 is an isometric view of an extruded section of a fixture havingthe cross-section of FIG. 17.

FIG. 19 is a front view of a fixture for use in a luminance application,for example to represent the letter “I.”

FIG. 20 is a front view of a fixture for use in a luminance application,representing the letter “L.”

FIG. 21 is a cross-sectional view of another example of an opticalcavity LED light fixture, as might be used for a “wall-washer”application.

FIG. 22 is an isometric view of an extruded section of a fixture havingthe cross-section of FIG. 21.

FIG. 23 is a cross-sectional view of another example of an opticalcavity LED light fixture, as might be used for a “wall-washer”application, using a combination of a white light source and a pluralityof primary color light sources.

FIG. 24 is a cross-sectional view of another example of an opticalcavity LED light fixture, in this case using a deflector and acombination of a white light source and a plurality of primary colorlight sources.

DETAILED DESCRIPTION

Reference now is made in detail to the examples illustrated in theaccompanying drawings and discussed below. FIG. 1 is a cross-sectionalillustration of a radiant energy distribution apparatus or system 10.For task lighting applications, the apparatus emits light in the visiblespectrum, although the system 10 may be used for lumination applicationsand/or with emissions in or extending into the infrared and/orultraviolet portions of the radiant energy spectrum.

The illustrated system 10 includes an optical cavity 11 having adiffusely reflective interior surface, to receive and combine radiantenergy of different colors/wavelengths. The cavity 11 may have variousshapes. The illustrated cross-section would be substantially the same ifthe cavity is hemispherical or if the cavity is semi-cylindrical withthe cross-section taken perpendicular to the longitudinal axis. Theoptical cavity in the examples discussed below is typically an opticalintegrating cavity.

The disclosed apparatus may use a variety of different structures orarrangements for the optical integrating cavity, examples of which arediscussed below relative to FIGS. 3–9 and 15 a–24. At least asubstantial portion of the interior surface(s) of the cavity exhibit(s)diffuse reflectivity. It is desirable that the cavity surface have ahighly efficient reflective characteristic, e.g. a reflectivity equal toor greater than 90%, with respect to the relevant wavelengths. In theexample of FIG. 1, the surface is highly diffusely reflective to energyin the visible, near-infrared, and ultraviolet wavelengths.

The cavity 11 may be formed of a diffusely reflective plastic material,such as a polypropylene having a 97% reflectivity and a diffusereflective characteristic. Such a highly reflective polypropylene isavailable from Ferro Corporation—Specialty Plastics Group, Filled andReinforced Plastics Division, in Evansville, Ind. Another example of amaterial with a suitable reflectivity is SPECTRALON. Alternatively, theoptical integrating cavity may comprise a rigid substrate having aninterior surface, and a diffusely reflective coating layer formed on theinterior surface of the substrate so as to provide the diffuselyreflective interior surface of the optical integrating cavity. Thecoating layer, for example, might take the form of a flat-white paint orwhite powder coat. A suitable paint might include a zinc-oxide basedpigment, consisting essentially of an uncalcined zinc oxide andpreferably containing a small amount of a dispersing agent. The pigmentis mixed with an alkali metal silicate vehicle-binder, which preferablyis a potassium silicate, to form the coating material. For moreinformation regarding the exemplary paint, attention is directed to U.S.patent application Ser. No. 09/866,516, which was filed May 29, 2001, byMatthew Brown, which issued as U.S. Pat. No. 6,700,112 on Mar. 2, 2004.

For purposes of the discussion, the cavity 11 in the apparatus 10 isassumed to be hemispherical. In the example, a hemispherical dome 13 anda substantially flat cover plate 15 form the optical cavity 11. At leastthe interior facing surfaces of the dome 13 and the cover plate 15 arehighly diffusely reflective, so that the resulting cavity 11 is highlydiffusely reflective with respect to the radiant energy spectrumproduced by the device 10. As a result, the cavity 11 is an integratingtype optical cavity. Although shown as separate elements, the dome andplate may be formed as an integral unit.

The optical integrating cavity 11 has an aperture 17 for allowingemission of combined radiant energy. In the example, the aperture 17 isa passage through the approximate center of the cover plate 15, althoughthe aperture may be at any other convenient location on the plate 15 orthe dome 13. Because of the diffuse reflectivity within the cavity 11,light within the cavity is integrated before passage out of the aperture17. In the examples, the apparatus 10 is shown emitting the combinedradiant energy downward through the aperture 17, for convenience.However, the apparatus 10 may be oriented in any desired direction toperform a desired application function, for example to provide visibleluminance to persons in a particular direction or location with respectto the fixture or to illuminate a different surface such as a wall,floor or table top. Also, the optical integrating cavity 11 may havemore than one aperture 17, for example, oriented to allow emission ofintegrated light in two or more different directions or regions.

The apparatus 10 also includes sources of radiant energy of differentwavelengths. In the first example, the sources are LEDs 19, two of whichare visible in the illustrated cross-section. The LEDs 19 supply radiantenergy into the interior of the optical integrating cavity 11. As shown,the points of emission into the interior of the optical integratingcavity are not directly visible through the aperture 17. At least thetwo illustrated LEDs emit radiant energy of different wavelengths, e.g.Red (R) and Green (G). Additional LEDs of the same or different colorsmay be provided. The cavity 11 effectively integrates the energy ofdifferent wavelengths, so that the integrated or combined radiant energyemitted through the aperture 17 includes the radiant energy of all thevarious wavelengths in relative amounts substantially corresponding tothe relative intensities of input into the cavity 11.

The source LEDs 19 can include LEDs of any color or wavelength.Typically, an array of LEDs for a visible light application includes atleast red, green, and blue LEDs. The integrating or mixing capability ofthe cavity 11 serves to project light of any color, including whitelight, by adjusting the intensity of the various sources coupled to thecavity. Hence, it is possible to control color rendering index (CRI), aswell as color temperature. The system 10 works with the totality oflight output from a family of LEDs 19. However, to provide coloradjustment or variability, it is not necessary to control the output ofindividual LEDs, except as they contribute to the totality. For example,it is not necessary to modulate the LED outputs. Also, the distributionpattern of the individual LEDs and their emission points into the cavityare not significant. The LEDs 19 can be arranged in any manner to supplyradiant energy within the cavity, although it is preferred that directview of the LEDs from outside the fixture is minimized or avoided.

In this example, light outputs of the LED sources 19 are coupleddirectly to openings at points on the interior of the cavity 11, to emitradiant energy directly into the interior of the optical integratingcavity. The LEDs may be located to emit light at points on the interiorwall of the element 13, although preferably such points would still bein regions out of the direct line of sight through the aperture 17. Forease of construction, however, the openings for the LEDs 19 are formedthrough the cover plate 15. On the plate 15, the openings/LEDs may be atany convenient locations.

The apparatus 10 also includes a control circuit 21 coupled to the LEDs19 for establishing output intensity of radiant energy of each of theLED sources. The control circuit 21 typically includes a power supplycircuit coupled to a source, shown as an AC power source 23. The controlcircuit 21 also includes an appropriate number of LED driver circuitsfor controlling the power applied to each of the individual LEDs 19 andthus the intensity of radiant energy supplied to the cavity 11 for eachdifferent wavelength. Control of the intensity of emission of thesources sets a spectral characteristic of the combined radiant energyemitted through the aperture 17 of the optical integrating cavity. Thecontrol circuit 21 may be responsive to a number of different controlinput signals, for example, to one or more user inputs as shown by thearrow in FIG. 1. Although not shown in this simple example, feedback mayalso be provided. Specific examples of the control circuitry arediscussed in more detail later.

The aperture 17 may serve as the system output, directing integratedcolor light to a desired area or region to be illuminated. Although notshown in this example, the aperture 17 may have a grate, lens ordiffuser (e.g. a holographic element) to help distribute the outputlight and/or to close the aperture against entry of moisture of debris.For some applications, the system 10 includes an additional deflector todistribute and/or limit the light output to a desired field ofillumination. A later embodiment, for example, uses a colliminator.

The color integrating energy distribution apparatus may also utilize oneor more conical deflectors having a reflective inner surface, toefficiently direct most of the light emerging from a light source into arelatively narrow field of view. Hence, the exemplary apparatus shown inFIG. 1 also comprises a conical deflector 25. A small opening at aproximal end of the deflector is coupled to the aperture 17 of theoptical integrating cavity 11. The deflector 25 has a larger opening 27at a distal end thereof. The angle and distal opening of the conicaldeflector 25 define an angular field of radiant energy emission from theapparatus 10. Although not shown, the large opening of the deflector maybe covered with a transparent plate or lens, or covered with a grating,to prevent entry of dirt or debris through the cone into the systemand/or to further process the output radiant energy.

The conical deflector may have a variety of different shapes, dependingon the particular lighting application. In the example, where cavity 11is hemispherical, the cross-section of the conical deflector istypically circular. However, the deflector may be somewhat oval inshape. In applications using a semi-cylindrical cavity, the deflectormay be elongated or even rectangular in cross-section. The shape of theaperture 17 also may vary, but will typically match the shape of thesmall end opening of the deflector 25. Hence, in the example, theaperture 17 would be circular. However, for a device with asemi-cylindrical cavity and a deflector with a rectangularcross-section, the aperture may be rectangular.

The deflector 25 comprises a reflective interior surface 29 between thedistal end and the proximal end. In some examples, at least asubstantial portion of the reflective interior surface 29 of the conicaldeflector exhibits specular reflectivity with respect to the integratedradiant energy. As discussed in U.S. Pat. No. 6,007,225, for someapplications, it may be desirable to construct the deflector 25 so thatat least some portion(s) of the inner surface 29 exhibit diffusereflectivity or exhibit a different degree of specular reflectivity(e.g., quasi-secular), so as to tailor the performance of the deflector25 to the particular application. For other applications, it may also bedesirable for the entire interior surface 29 of the deflector 25 to havea diffuse reflective characteristic. In such cases, the deflector 25 maybe constructed using materials similar to those taught above forconstruction of the optical integrating cavity 11.

In the illustrated example, the large distal opening 27 of the deflector25 is roughly the same size as the cavity 11. In some applications, thissize relationship may be convenient for construction purposes. However,a direct relationship in size of the distal end of the deflector and thecavity is not required. The large end of the deflector may be larger orsmaller than the cavity structure. As a practical matter, the size ofthe cavity is optimized to provide the integration or combination oflight colors from the desired number of LED sources 19. The size, angleand shape of the deflector determine the area that will be illuminatedby the combined or integrated light emitted from the cavity 11 via theaperture 17.

In the examples, each source of radiant energy of a particularwavelength comprises one or more light emitting diodes (LEDs). Withinthe chamber, it is possible to process light received from any desirablenumber of such LEDs. Hence, in several examples, the sources maycomprise one or more LEDs for emitting light of a first color, and oneor more LEDs for emitting light of a second color, wherein the secondcolor is different from the first color. In a similar fashion, theapparatus may include additional sources comprising one or more LEDs ofa third color, a fourth color, etc. To achieve the highest colorrendering index (CRI), the LED array may include LEDs of variouswavelengths that cover virtually the entire visible spectrum. Exampleswith additional sources of substantially white light are discussedlater.

FIGS. 2A to 2E are detail views of the light fixture components of anexample of a system of the type described above relative to FIG. 1. FIG.2A is an exploded side-view of the set 200 of the fixture components,and FIG. 2B is a similar view but showing some of those components incross-section. As shown, the fixture elements 200 include twoquarter-spherical domes 201 and 203 that are joined to form the opticalintegrating cavity and a portion of an LED mounting structure. The domes201 and 203 are formed of a rigid material having a highly diffuselyreflective inner surface, as discussed above.

Each dome includes a boss 205 or 207 near the back apex thereof. Whenthe domes 201 and 203 are joined to form the cavity, the bosses 205 and207 together form a ring-shaped back shoulder that can be used formounting the fixture.

The illustrated components also include twelve LEDs 209 (six of whichare visible in FIGS. 2A and 2B). The LEDs 209 provide differentwavelengths of light as discussed earlier. In one example, the deviceincludes six Red LEDs, three Green LEDs and three Blue LEDs.

FIG. 2D is an end view of the cavity assembly, that is to say, showingthe two domes 201 and 203 joined together. As shown in cross-section inFIG. 2B, each dome includes an inwardly extending half-circular shoulder211 or 213. When the domes are joined as in FIG. 2D, these shoulders211, 213 together form a ring-shaped cover of the cavity. Thering-shaped cover provides one half of a sandwich like structure, forsupporting the LEDs 209. The central opening 215 of the cover forms theaperture of the optical integrating cavity. Openings 221 through thecover allow passage of light from the LEDs 209 into the interior of thecavity.

The shoulders 211 and 213 include two half-circular bosses aroundrespective portions of the inner opening 215. When the two halves of thecavity structure are joined (FIG. 2D), these bosses form two innerflanges 217 and 219, extending toward the direction of intendedillumination. The groove formed between the flanges 217 and 219 receivesthe distal end of the conical deflector 223. FIG. 2C is an end view ofthe deflector 223. In the example, the entire inner surface 225 of thedeflector 223 has a specular reflective characteristic.

As discussed and shown, the cavity assembly includes shoulders 211 and213, which together form the cover plate of the cavity and form half ofthe LED support structure. The LEDs 209 are attached to the back (upwardside in FIGS. 2A and 2B) of an LED support ring 227, which provides theother half of the LED support structure. The LED support ring 227 may bemade of a suitable rigid material, which is resistant to the heatgenerated by the LEDs. For example, the LED support ring 227 may beconstructed of aluminum, to provide the necessary structural support andto act as a heat sink to wick away a substantial portion of the heatgenerated by the attached LEDs 209. Although not shown, ventilation orother cooling elements may also be provided.

In this example, for each LED 209, there are six small mounting holes229 through the LED support ring 227 (see FIG. 2E). The LED support ring227 also has six outwardly extending ‘tabs’ 231 around its perimeter, tofacilitate mounting. Although not shown for convenience, the cavityassembly (FIG. 2D) has three small bosses/tabs around the outside thatmate to three of the six tabs 231 on the LED support ring 227.

The central passage 233 of the LED support ring 227 is somewhat largerin diameter than the proximal (small) end of the conical deflector 223.During assembly, the proximal end of the conical deflector 223 passesthrough the opening 233 and mates in the groove formed between thegroove formed between the flanges 217 and 219. In this way, the proximalend of the deflector surrounds the aperture 215. Those skilled in theart will recognize that the structure of FIGS. 2A to 2E is exemplary andother structures may be used, for example, to mount desired numbers ofLEDs and/or to couple/attach the deflector to the aperture.

FIGS. 3 and 4 illustrate another example of a radiant energydistribution apparatus or system. FIG. 3 shows the overall system 30,including the fixture and the control circuitry. The fixture is shown incross-section. FIG. 4 is a bottom view of the fixture. The system 30 isgenerally similar the system 10. For example, the system 30 may utilizeessentially the same type of control circuit 21 and power source 23, asin the earlier example. However, the shape of the optical integratingcavity and the deflector are somewhat different.

The optical integrating cavity 31 has a diffusely reflective interiorsurface. In this example, the cavity 31 has a shape corresponding to asubstantial portion of a cylinder. In the cross-sectional view of FIG. 3(taken across the longitudinal axis of the cavity), the cavity 31appears to have an almost circular shape. In this example, the cavity 31is formed by a cylindrical element 33. At least the interior surface ofthe element 33 is highly diffusely reflective, so that the resultingoptical cavity 31 is highly diffusely reflective and functions as anintegrating cavity, with respect to the radiant energy spectrum producedby the system 30.

The optical integrating cavity 31 has an aperture 35 for allowingemission of combined radiant energy. In this example, the aperture 35 isa rectangular passage through the wall of the cylindrical element 33.Because of the diffuse reflectivity within the cavity 31, light withinthe cavity is integrated before passage out of the aperture 35.

The apparatus 30 also includes sources of radiant energy of differentwavelengths. In this example, the sources comprise LEDs 37, 39. The LEDsare mounted in openings through the wall of the cylindrical element 33,to essentially form two rows of LEDs on opposite sides of the aperture35. The positions of these openings, and thus the positions of the LEDs37 and 39, typically are such that the LED outputs are not directlyvisible through the aperture 35, otherwise the locations are a matter ofarbitrary choice.

Thus, the LEDs 37 and 39 supply radiant energy into the interior of theoptical integrating cavity 31, through openings at points on theinterior surface of the optical integrating cavity not directly visiblethrough the aperture 35. A number of the LEDs emit radiant energy ofdifferent wavelengths. For example, arbitrary pairs of the LEDs 37, 39might emit four different colors of light, e.g. Red, Green and Blue asprimary colors and a fourth color chosen to provide an increasedvariability of the spectral characteristic of the integrated radiantenergy. One or more white light sources, e.g. white LEDs, also may beprovided.

Alternatively, a number of the LEDs may be initially active LEDs,whereas others are initially inactive sleeper LEDs. For example, theinitially active LEDs might include two Red LEDs, two Green LEDs and aBlue LED; and the sleeper LEDs might include one Red LED, one Green LEDand one Blue LED.

The control circuit 21 controls the power provided to each of the LEDs37 and 39. The cavity 31 effectively integrates the energy of differentwavelengths, from the various LEDs 37 and 39, so that the integratedradiant energy emitted through the aperture 35 includes the radiantenergy of all the various wavelengths. Control of the intensity ofemission of the sources, by the control circuit 21, sets a spectralcharacteristic of the combined radiant energy emitted through theaperture 35. If sleeper LEDs are provided, the control also activatesone or more dormant LEDs, on an “as-needed” basis, when extra output ofa particular wavelength or color is required.

The color integrating energy distribution apparatus 30 may also includea deflector 41 having a specular reflective inner surface 43, toefficiently direct most of the light emerging from the aperture into arelatively narrow field of view. The deflector 41 expands outward from asmall end thereof coupled to the aperture 35. The deflector 41 has alarger opening 45 at a distal end thereof. The angle of the side wallsof the deflector and the shape of the distal opening 45 of the deflector41 define an angular field of radiant energy emission from the apparatus30.

As noted above, the deflector may have a variety of different shapes,depending on the particular lighting application. In the example, wherethe cavity 31 is substantially cylindrical, and the aperture isrectangular, the cross-section of the deflector 41 (viewed across thelongitudinal axis as in FIG. 3) typically appears conical, since thedeflector expands outward as it extends away from the aperture 35.However, when viewed on-end (bottom view—FIG. 4), the openings aresubstantially rectangular, although they may have somewhat roundedcorners. Alternatively, the deflector 41 may be somewhat oval in shape.The shapes of the cavity and the aperture may vary, for example, to haverounded ends, and the deflector may be contoured to match the aperture.

The deflector 41 comprises a reflective interior surface 43 between thedistal end and the proximal end. In several examples, at least asubstantial portion of the reflective interior surface 43 of the conicaldeflector exhibits specular reflectivity with respect to the combinedradiant energy, although different reflectivity may be provided, asnoted in the discussion of FIG. 1.

If provided, “sleeper” LEDs would be activated only when needed tomaintain the light output, color, color temperature, and/or thermaltemperature. As discussed later with regard to an exemplary controlcircuit, the system 30 could have a color sensor coupled to providefeedback to the control circuit 21. The sensor could be within thecavity or the deflector or at an outside point illuminated by theintegrated light from the fixture.

As LEDs age, they continue to operate, but at a reduced output level.The use of the sleeper LEDs greatly extends the lifecycle of thefixtures. Activating a sleeper (previously inactive) LED, for example,provides compensation for the decrease in output of the originallyactive LED. There is also more flexibility in the range of intensitiesthat the fixtures may provide.

In the examples discussed above relative to FIG. 1 to 4, the LED sourceswere coupled directly to openings at the points on the interior of thecavity, to emit radiant energy directly into the interior of the opticalintegrating cavity. It is also envisioned that the sources may besomewhat separated from the cavity, in which case, the device mightinclude optical fibers or other forms of light guides coupled betweenthe sources and the optical integrating cavity, to supply radiant energyfrom the sources to the emission points into the interior of the cavity.FIG. 5 depicts such a system 50, which uses optical fibers.

The system 50 includes an optical integrating cavity 51, an aperture 53and a deflector with a reflective interior surface 55, similar to thosein the earlier embodiments. The interior surface of the opticalintegrating cavity 51 is highly diffusely reflective, whereas thedeflector surface 55 exhibits a specular reflectivity.

The system 50 includes a control circuit 21 and power source 23, as inthe earlier embodiments. In the system 50, the radiant energy sourcescomprise LEDs 59 of three different wavelengths, e.g. to provide Red,Green and Blue light respectively. The sources may also include one ormore additional LEDs 61, either white or of a different color or for useas ‘sleepers,’ similar to the example of FIGS. 3 and 4. In this example(FIG. 5), the cover plate 63 of the cavity 51 has openings into whichare fitted the light emitting distal ends of optical fibers 65. Theproximal light receiving ends of the fibers 65 are coupled to receivelight emitted by the LEDs 59 (and 61 if provided). In this way, the LEDsources 59, 61 may be separate from the chamber 51, for example, toallow easier and more effective dissipation of heat from the LEDs. Thefibers 65 transport the light from the LED sources 59, 61 to the cavity51. The cavity 51 integrates the different colors of light from the LEDsas in the earlier examples and supplies combined light out through theaperture 53. The deflector, in turn, directs the combined light to adesired field. Again, the intensity control by the circuit 21 adjuststhe amount or intensity of the light of each type provided by the LEDsources and thus controls the spectral characteristic of the combinedlight output.

A number of different examples of control circuits are discussed below.In one example, the control circuitry comprises a color sensor coupledto detect color distribution in the integrated radiant energy.Associated logic circuitry, responsive to the detected colordistribution, controls the output intensity of the various LEDs, so asto provide a desired color distribution in the integrated radiantenergy. In an example using sleeper LEDs, the logic circuitry isresponsive to the detected color distribution to selectively activatethe inactive light emitting diodes as needed, to maintain the desiredcolor distribution in the integrated radiant energy.

To provide a uniform output distribution from the apparatus, it is alsopossible to construct the optical cavity so as to provide constructiveocclusion. Constructive Occlusion type transducer systems utilize anelectrical/optical transducer optically coupled to an active area of thesystem, typically the aperture of a cavity or an effective apertureformed by a reflection of the cavity. The systems utilize diffuselyreflective surfaces, such that the active area exhibits a substantiallyLambertian characteristic. A mask occludes a portion of the active areaof the system, in the examples, the aperture of the cavity or theeffective aperture formed by the cavity reflection, in such a manner asto achieve a desired response or output performance characteristic forthe system. In examples of the present systems using constructiveocclusion, the optical integrating cavity comprises a base, a mask and acavity in either the base or the mask. The mask would have a diffuselyreflective surface facing toward the aperture. The mask is sized andpositioned relative to the active area so as to constructively occludethe active area. It may be helpful to consider two examples usingconstructive occlusion.

FIGS. 6 and 7 depict a first, simple embodiment of a light distributorapparatus or system 70, for projecting integrated multi-wavelength lightwith a tailored intensity distribution, using the principles ofconstructive occlusion. In the cross-section illustration, the system 70is oriented to provide downward illumination. Such a system might bemounted in or suspended from a ceiling or canopy or the like. Thoseskilled in the art will recognize that the designer may choose to orientthe system 70 in different directions, to adapt the system to otherlighting applications.

The lighting system 70 includes a base 73, having or forming a cavity75, and adjacent shoulders 77 and 79, constructed in a manner similar tothe elements forming integrating cavities in the earlier examples. Inparticular, the interior of the cavity 75 is diffusely reflective, andthe down-facing surfaces of shoulders 77 and 79 may be reflective. Ifthe shoulder surfaces are reflective, they may be specular or diffuselyreflective. A mask 81 is disposed between the cavity aperture 85 and thefield to be illuminated. In this symmetrical embodiment, the interiorwall of a half-cylindrical base 73 forms the cavity; therefore theaperture 85 is rectangular. The shoulders 77 formed along the sides ofthe aperture 85 are rectangular. If the base were circular, with ahemispherical cavity, the shoulders typically would form a ring that maypartially or completely surround the aperture.

In many constructive occlusion embodiments, the cavity 75 comprises asubstantial segment of a sphere. For example, the cavity may besubstantially hemispherical, as in earlier examples. However, thecavity's shape is not of critical importance. A variety of other shapesmay be used. In the illustrated example, the half-cylindrical cavity 75has a rectangular aperture, and if extended longitudinally, therectangular aperture may approach a nearly linear aperture (slit).Practically any cavity shape is effective, so long as it has a diffusereflective inner surface. A hemisphere or the illustrated half-cylindershape are preferred for the ease in modeling for the light output towardthe field of intended illumination and the attendant ease ofmanufacture. Also, sharp corners tend to trap some reflected energy andreduce output efficiency.

For purposes of constructive occlusion, the base 73 may be considered tohave an active optical area, preferably exhibiting a substantiallyLambertian energy distribution. Where the cavity is formed in the base,for example, the planar aperture 85 formed by the rim or perimeter ofthe cavity 75 forms the active surface with substantially Lambertiandistribution of energy emerging through the aperture. As shown in alater embodiment, the cavity may be formed in the facing surface of themask. In such a system, the surface of the base may be a diffuselyreflective surface, therefore the active area on the base wouldessentially be the mirror image of the cavity aperture on the basesurface, that is to say the area reflecting energy emerging from thephysical aperture of the cavity in the mask.

The mask 81 constructively occludes a portion of the optically activearea of the base with respect to the field of intended illumination. Inthe example of FIG. 6, the optically active area is the aperture 85 ofthe cavity 75; therefore the mask 81 occludes a substantial portion ofthe aperture 85, including the portion of the aperture on and about theaxis of the mask and cavity system. The surface of the mask 81 facingtowards the aperture 85 is reflective. Although it may be specular,typically this surface is diffusely reflective.

The relative dimensions of the mask 81 and aperture 85, for example therelative widths (or diameters or radii in a more circular system) aswell as the distance of the mask 81 away from the aperture 85, controlthe constructive occlusion performance characteristics of the lightingsystem 70. Certain combinations of these parameters produce a relativelyuniform emission intensity with respect to angles of emission, over awide portion of the field of view about the system axis (verticallydownward in FIG. 6), covered principally by the constructive occlusion.Other combinations of size and height result in a system performancethat is uniform with respect to a wide planar surface perpendicular tothe system axis at a fixed distance from the active area.

The shoulders 77, 79 also are reflective and therefore deflect at leastsome light downward. The shoulders (and side surfaces of the mask)provide additional optical processing of combined light from the cavity.The angles of the shoulders and the reflectivity of the surfaces thereoffacing toward the region to be illuminated by constructive occlusionalso contribute to the intensity distribution over that region. In theillustrated example, the reflective shoulders are horizontal, althoughthey may be angled somewhat downward from the plane of the aperture.

With respect to the energy of different wavelengths, the interior spaceformed between the cavity 75 and the facing surface of the mask 81operates as an optical integrating cavity, in essentially the samemanner as the integrating cavities in the previous embodiments. Again,the LEDs provide light of a number of different colors, and thus ofdifferent wavelengths. The optical cavity combines the light of multiplecolors supplied from the LEDs 87. The control circuit 21 controls theamount of each color of light supplied to the chamber and thus theproportion thereof included in the combined output light. Theconstructive occlusion serves to distribute that light in a desiredmanner over a field or area that the system 70 is intended toilluminate, with a tailored intensity distribution.

The LEDs 87 could be located at (or coupled by optical fiber to emitlight) from any location or part of the surface of the cavity 75.Preferably, the LED outputs are not directly visible through theun-occluded portions of the aperture 85 (between the mask and the edgeof the cavity). In examples of the type shown in FIGS. 6 and 7, theeasiest way to so position the LED outputs is to mount the LEDs 87 (orprovide fibers or the like) so as to supply light to the chamber throughopenings through the mask 81.

FIG. 7 also provides an example of an arrangement of the LEDs in whichthere are both active and inactive (sleeper) LEDs of the various colors.As shown, the active part of the array of LEDs 87 includes two Red LEDs(R), one Green LED (G) and one Blue LED (B). The initially inactive partof the array of LEDs 87 includes two Red sleeper LEDs (RS), one Greensleeper LED (GS) and one Blue sleeper LED (BS). If other wavelengths orwhite light sources are desired, the apparatus may include an active LEDof the other color (O) as well as a sleeper LED of the other color (OS).The precise number, type, arrangement and mounting technique of the LEDsand the associated ports through the mask 81 are not critical. Thenumber of LEDs, for example, is chosen to provide a desired level ofoutput energy (intensity), for a given application.

The system 70 includes a control circuit 21 and power source 23. Theseelements control the operation and output intensity of each LED 87. Theindividual intensities determine the amount of each color light includedin the integrated and distributed output. The control circuit 21functions in essentially the same manner as in the other examples.

FIGS. 8 and 9 illustrate a second constructive occlusion example. Inthis example, the physical cavity is actually formed in the mask, andthe active area of the base is a flat reflective panel of the base.

The illustrated system 90 comprises a flat base panel 91, a mask 93, LEDlight sources 95, and a conical deflector 97. The system 90 iscircularly symmetrical about a vertical axis, although it could berectangular or have other shapes. The base 91 includes a flat centralregion 99 between the walls of the deflector 97. The region 99 isreflective and forms or contains the active optical area on the basefacing toward the region or area to be illuminated by the system 90.

The mask 93 is positioned between the base 91 and the region to beilluminated by constructive occlusion. For example, in the orientationshown, the mask 93 is above the active optical area 99 of the base 91,for example to direct light toward a ceiling for indirect illumination.Of course, the mask and cavity system could be inverted to serve as adownlight for task lighting applications, or the mask and cavity systemcould be oriented to emit light in directions appropriate for otherapplications.

In this example, the mask 93 contains the diffusely reflective cavity101, constructed in a manner similar to the integrating cavities in theearlier examples. The physical aperture 103 of the cavity 101 and of anydiffusely reflective surface(s) of the mask 93 that may surround thataperture form an active optical area on the mask 93. Such an active areaon the mask faces away from the region to be illuminated and toward theactive surface 99 on the base 91. The surface 99 is reflective,preferably with a diffuse characteristic. The surface 99 of the base 91essentially acts to produce a diffused mirror image of the mask 93 withits cavity 101 as projected onto the base area 99. The reflection formedby the active area of the base becomes the effective aperture of theoptical integrating cavity (between the mask and base) when the fixtureis considered from the perspective of the area of intended illumination.The surface area 99 reflects energy emerging from the aperture 103 ofthe cavity 101 in the mask 93. The mask 93 in turn constructivelyoccludes light diffused from the active base surface 99 with respect tothe region illuminated by the system 90. The dimensions and relativepositions of the mask and active region on the base control theperformance of the system, in essentially the same manner as in the maskand cavity system of FIGS. 6 and 7.

The system 90 includes a control circuit 21 and associated power source23, for supplying controlled electrical power to the LED sources 95. Inthis example, the LEDs emit light through openings through the base 91,preferably at points not directly visible from outside the system. TheLEDs 95 supply various wavelengths of light, and the circuit 21 controlsthe power of each LED, to control the amount of each color of light inthe combined output, as discussed above relative to the other examples.

The base 91 could have a flat ring-shaped shoulder with a reflectivesurface. In this example, however, the shoulder is angled toward thedesired field of illumination to form a conical deflector 97. The innersurface of the deflector 97 is reflective, as in the earlier examples.

The deflector 97 has the shape of a truncated cone, in this example,with a circular lateral cross section. The cone has two circularopenings. The cone tapers from the large end opening to the narrow endopening, which is coupled to the active area 99 of the base 91. Thenarrow end of the deflector cone receives light from the surface 99 andthus from diffuse reflections between the base and the mask.

The entire area of the inner surface of the cone 97 is reflective. Atleast a portion of the reflective surface is specular, as in thedeflectors of the earlier examples. The angle of the wall(s) of theconical deflector 97 substantially corresponds to the angle of thedesired field of view of the illumination intended for the system 90.Because of the reflectivity of the wall of the cone 97, most if not allof the light reflected by the inner surface thereof would at leastachieve an angle that keeps the light within the field of view.

The LED light sources 95 emit multiple wavelengths of light into themask cavity 101. The light sources 95 may direct some light toward theinner surface of the deflector 97. Light rays impacting on the diffuselyreflective surfaces, particularly those on the inner surface of thecavity 101 and the facing surface 99 of the base 91, reflect and diffuseone or more times within the confines of the system and emerge throughthe gap between the perimeter of the active area 99 of the base and theouter edge of the mask 93. The mask cavity 101 and the base surface 99function as an optical integrating cavity with respect to the light ofvarious wavelengths, and the gap becomes the actual integrating cavityaperture from which combined light emerges. The light emitted throughthe gap and/or reflected from the surface of the inner surface of thedeflector 97 irradiates a region (upward in the illustrated orientation)with a desired intensity distribution and with a desired spectralcharacteristic, essentially as in the earlier examples.

Additional information regarding constructive occlusion based systemsfor generating and distributing radiant energy may be found in commonlyassigned U.S. Pat. Nos. 6,342,695, 6,334,700, 6,286,979, 6,266,136 and6,238,077. The color integration principles discussed herein may beadapted to any of the constructive occlusion devices discussed in thosepatents.

The inventive devices have numerous applications, and the outputintensity and spectral characteristic may be tailored and/or adjusted tosuit the particular application. For example, the intensity of theintegrated radiant energy emitted through the aperture may be at a levelfor use in a rumination application or at a level sufficient for a tasklighting application. A number of other control circuit features alsomay be implemented. For example, the control may maintain a set colorcharacteristic in response to feedback from a color sensor. The controlcircuitry may also include a temperature sensor. In such an example, thelogic circuitry is also responsive to the sensed temperature, e.g. toreduce intensity of the source outputs to compensate for temperatureincreases. The control circuitry may include an appropriate device formanually setting the desired spectral characteristic, for example, oneor more variable resistors or one or more dip switches, to allow a userto define or select the desired color distribution.

Automatic controls also are envisioned. For example, the controlcircuitry may include a data interface coupled to the logic circuitry,for receiving data defining the desired color distribution. Such aninterface would allow input of control data from a separate or evenremote device, such as a personal computer, personal digital assistantor the like. A number of the devices, with such data interfaces, may becontrolled from a common central location or device.

The control may be somewhat static, e.g. set the desired color referenceindex or desired color temperature and the overall intensity, and leavethe device set-up in that manner for an indefinite period. The apparatusalso may be controlled dynamically, for example, to provide specialeffects lighting. Where a number of the devices are arranged in a largetwo-dimensional array, dynamic control of color and intensity of eachunit could even provide a video display capability, for example, for useas a “Jumbo Tron” view screen in a stadium or the like. In productlighting or in personnel lighting (for studio or theater work), thelighting can be adjusted for each product or person that is illuminated.Also, such light settings are easily recorded and reused at a later timeor even at a different location using a different system.

To appreciate the features and examples of the control circuitryoutlined above, it may be helpful to consider specific examples withreference to appropriate diagrams.

FIG. 10 is a block diagram of exemplary circuitry for the sources andassociated control circuit, providing digital programmable control,which may be utilized with a light integrating fixture of the typedescribed above. In this circuit example, the sources of radiant energyof the various types takes the form of an LED array 111. The array 111comprises two or more LEDs of each of the three primary colors, redgreen and blue, represented by LED blocks 113, 115 and 117. For example,the array may comprise six red LEDs 113, three green LEDs 115 and threeblue LEDs 117.

The LED array in this example also includes a number of additional or“other” LEDs 119. There are several types of additional LEDs that are ofparticular interest in the present discussion. One type of additionalLED provides one or more additional wavelengths of radiant energy forintegration within the chamber. The additional wavelengths may be in thevisible portion of the light spectrum, to allow a greater degree ofcolor adjustment. Alternatively, the additional wavelength LEDs mayprovide energy in one or more wavelengths outside the visible spectrum,for example, in the infrared range or the ultraviolet range.

The second type of additional LED that may be included in the system isa sleeper LED. As discussed above, some LEDs would be active, whereasthe sleepers would be inactive, at least during initial operation. Usingthe circuitry of FIG. 10 as an example, the Red LEDs 113, Green LEDs 115and Blue LEDs 117 might normally be active. The LEDs 119 would besleeper LEDs, typically including one or more LEDs of each color used inthe particular system.

The third type of other LED of interest is a white LED. For whitelighting applications, one or more white LEDs provide increasedintensity. The primary color LEDs then provide light for coloradjustment and/or correction.

The electrical components shown in FIG. 10 also include an LED controlsystem 120. The system 120 includes driver circuits for the various LEDsand a microcontroller. The driver circuits supply electrical current tothe respective LEDs 113 to 119 to cause the LEDs to emit light. Thedriver circuit 121 drives the Red LEDs 113, the driver circuit 123drives the green LEDs 115, and the driver circuit 125 drives the BlueLEDs 117. In a similar fashion, when active, the driver circuit 127provides electrical current to the other LEDs 119. If the other LEDsprovide another color of light, and are connected in series, there maybe a single driver circuit 127. If the LEDs are sleepers, it may bedesirable to provide a separate driver circuit 127 for each of the LEDs119. The intensity of the emitted light of a given LED is proportionalto the level of current supplied by the respective driver circuit.

The current output of each driver circuit is controlled by the higherlevel logic of the system. In this digital control example, that logicis implemented by a programmable microcontroller 129, although thoseskilled in the art will recognize that the logic could take other forms,such as discrete logic components, an application specific integratedcircuit (ASIC), etc.

The LED driver circuits and the microcontroller 129 receive power from apower supply 131, which is connected to an appropriate power source (notseparately shown). For most task-lighting applications, the power sourcewill be an AC line current source, however, some applications mayutilize DC power from a battery or the like. The power supply 129converts the voltage and current from the source to the levels needed bythe driver circuits 121–127 and the microcontroller 129.

A programmable microcontroller typically includes or has coupled theretorandom-access memory (RAM) for storing data and read-only memory (ROM)and/or electrically erasable read only memory (EEROM) for storingcontrol programming and any pre-defined operational parameters, such aspre-established light ‘recipes.’ The microcontroller 129 itselfcomprises registers and other components for implementing a centralprocessing unit (CPU) and possibly an associated arithmetic logic unit.The CPU implements the program to process data in the desired manner andthereby generate desired control outputs.

The microcontroller 129 is programmed to control the LED driver circuits121–127 to set the individual output intensities of the LEDs to desiredlevels, so that the combined light emitted from the aperture of thecavity has a desired spectral characteristic and a desired overallintensity. The microcontroller 129 may be programmed to essentiallyestablish and maintain or preset a desired ‘recipe’ or mixture of theavailable wavelengths provided by the LEDs used in the particularsystem. The microcontroller 129 receives control inputs specifying theparticular ‘recipe’ or mixture, as will be discussed below. To insurethat the desired mixture is maintained, the microcontroller receives acolor feedback signal from an appropriate color sensor. Themicrocontroller may also be responsive to a feedback signal from atemperature sensor, for example, in or near the optical integratingcavity.

The electrical system will also include one or more control inputs 133for inputting information instructing the microcontroller 129 as to thedesired operational settings. A number of different types of inputs maybe used and several alternatives are illustrated for convenience. Agiven installation may include a selected one or more of the illustratedcontrol input mechanisms.

As one example, user inputs may take the form of a number ofpotentiometers 135. The number would typically correspond to the numberof different light wavelengths provided by the particular LED array 111.The potentiometers 135 typically connect through one or more analog todigital conversion interfaces provided by the microcontroller 129 (or inassociated circuitry). To set the parameters for the integrated lightoutput, the user adjusts the potentiometers 135 to set the intensity foreach color. The microcontroller 129 senses the input settings andcontrols the LED driver circuits accordingly, to set correspondingintensity levels for the LEDs providing the light of the variouswavelengths.

Another user input implementation might utilize one or more dip switches137. For example, there might be a series of such switches to input acode corresponding to one of a number of recipes. The memory used by themicrocontroller 129 would store the necessary intensity levels for thedifferent color LEDs in the array 111 for each recipe. Based on theinput code, the microcontroller 129 retrieves the appropriate recipefrom memory. Then, the microcontroller 129 controls the LED drivercircuits 121–127 accordingly, to set corresponding intensity levels forthe LEDs 113–119 providing the light of the various wavelengths.

As an alternative or in addition to the user input in the form ofpotentiometers 135 or dip switches 137, the microcontroller 129 may beresponsive to control data supplied from a separate source or a remotesource. For that purpose, some versions of the system will include oneor more communication interfaces. One example of a general class of suchinterfaces is a wired interface 139. One type of wired interfacetypically enables communications to and/or from a personal computer orthe like, typically within the premises in which the fixture operates.Examples of such local wired interfaces include USB, RS-232, andwire-type local area network (LAN) interfaces. Other wired interfaces,such as appropriate modems, might enable cable or telephone linecommunications with a remote computer, typically outside the premises.Other examples of data interfaces provide wireless communications, asrepresented by the interface 141 in the drawing. Wireless interfaces,for example, use radio frequency (RF) or infrared (IR) links. Thewireless communications may be local on-premises communications,analogous to a wireless local area network (WLAN). Alternatively, thewireless communications may enable communication with a remote deviceoutside the premises, using wireless links to a wide area network.

As noted above, the electrical components may also include one or morefeedback sensors 143, to provide system performance measurements asfeedback signals to the control logic, implemented in this example bythe microcontroller 129. A variety of different sensors may be used,alone or in combination, for different applications. In the illustratedexamples, the set 143 of feedback sensors includes a color sensor 145and a temperature sensor 147. Although not shown, other sensors, such asan overall intensity sensor may be used. The sensors are positioned inor around the system to measure the appropriate physical condition, e.g.temperature, color, intensity, etc.

The color sensor 145, for example, is coupled to detect colordistribution in the integrated radiant energy. The color sensor may becoupled to sense energy within the optical integrating cavity, withinthe deflector (if provided) or at a point in the field illuminated bythe particular system. Various examples of appropriate color sensors areknown. For example, the color sensor may be a digital compatible sensor,of the type sold by TAOS, Inc. Another suitable sensor might use thequadrant light detector disclosed in U.S. Pat. No. 5,877,490, withappropriate color separation on the various light detector elements (seeU.S. Pat. No. 5,914,487 for discussion of the color analysis).

The associated logic circuitry, responsive to the detected colordistribution, controls the output intensity of the various LEDs, so asto provide a desired color distribution in the integrated radiantenergy, in accord with appropriate settings. In an example using sleeperLEDs, the logic circuitry is responsive to the detected colordistribution to selectively activate the inactive light emitting diodesas needed, to maintain the desired color distribution in the integratedradiant energy. The color sensor measures the color of the integratedradiant energy produced by the system and provides a color measurementsignal to the microcontroller 129. If using the TAOS, Inc. color sensor,for example, the signal is a digital signal derived from a color tofrequency conversion.

The temperature sensor 147 may be a simple thermoelectric transducerwith an associated analog to digital converter, or a variety of othertemperature detectors may be used. The temperature sensor is positionedon or inside of the fixture, typically at a point that is near the LEDsor other sources that produce most of the system heat. The temperaturesensor 147 provides a signal representing the measured temperature tothe microcontroller 129. The system logic, here implemented by themicrocontroller 129, can adjust intensity of one or more of the LEDs inresponse to the sensed temperature, e.g. to reduce intensity of thesource outputs to compensate for temperature increases. The program ofthe microcontroller 129, however, would typically manipulate theintensities of the various LEDs so as to maintain the desired colorbalance between the various wavelengths of light used in the system,even though it may vary the overall intensity with temperature. Forexample, if temperature is increasing due to increased drive current tothe active LEDs (with increased age or heat), the controller maydeactivate one or more of those LEDs and activate a corresponding numberof the sleepers, since the newly activated sleeper(s) will providesimilar output in response to lower current and thus produce less heat.

The above discussion of FIG. 10 related to programmed digitalimplementations of the control logic. Those skilled in the art willrecognize that the control also may be implemented using analogcircuitry. FIG. 11 is a circuit diagram of a simple analog control for alighting apparatus (e.g. of the type shown in FIG. 1) using Red, Greenand Blue LEDs. The user establishes the levels of intensity for eachtype of radiant energy emission (Red, Green or Blue) by operating acorresponding one of the potentiometers. The circuitry essentiallycomprises driver circuits for supplying adjustable power to two or threesets of LEDs (Red, Green and Blue) and analog logic circuitry foradjusting the output of each driver circuit in accord with the settingof a corresponding potentiometer. Additional potentiometers andassociated circuits would be provided for additional colors of LEDs.Those skilled in the art should be able to implement the illustratedanalog driver and control logic of FIG. 11 without further discussion.

The systems described above have a wide range of applications, wherethere is a desire to set or adjust color provided by a lighting fixture.These include task lighting applications, signal light applications, aswells as applications for illuminating an object or person. Somelighting applications involve a common overall control strategy for anumber of the systems. As noted in the discussion of FIG. 10, thecontrol circuitry may include a communication interface 139 or 141allowing the microcontroller 129 to communicate with another processingsystem. FIG. 12 illustrates an example in which control circuits 21 of anumber of the radiant energy generation systems with the lightintegrating and distribution type fixture communicate with a mastercontrol unit 151 via a communication network 153. The master controlunit 151 typically is a programmable computer with an appropriate userinterface, such as a personal computer or the like. The communicationnetwork 153 may be a LAN or a wide area network, of any desired type.The communications allow an operator to control the color and outputintensity of all of the linked systems, for example to provide combinedlighting effects.

The commonly controlled lighting systems may be arranged in a variety ofdifferent ways, depending on the intended use of the systems. FIG. 13for example, shows a somewhat random arrangement of lighting systems.The circles represent the output openings of those systems, such as thelarge opening of the system deflectors. The dotted lines represent thefields of the emitted radiant energy. Such an arrangement of lightingsystems might be used to throw desired lighting on a wall or otherobject and may allow the user to produce special lighting effects atdifferent times. Another application might involve providing differentcolor lighting for different speakers during a television program, forexample, on a news program, panel discussion or talk show.

The commonly controlled radiant energy emission systems also may bearranged in a two-dimensional array or matrix. FIG. 14 shows an exampleof such an array. Again, circles represent the output openings of thosesystems. In this example of an array, the outputs are tightly packed.Each output may serve as a color pixel of a large display system.Dynamic control of the outputs therefore can provide a video displayscreen, of the type used as jumbo-trons in stadiums or the like.

In the examples above, a deflector, mask or shoulder was used to providefurther optical processing of the integrated light emerging from theaperture of the fixture. A variety of other optical processing devicesmay be used in place of or in combination with any of those opticalprocessing elements. Examples include various types of diffusers,collimators, variable focus mechanisms, and iris or aperture sizecontrol mechanisms. Several of these examples are shown in FIGS. 15–16.

FIGS. 15A to 15C are cross-sectional views of several examples ofoptical cavity LED fixtures using various forms of secondary opticalprocessing elements to process the integrated energy emitted through theaperture. Although similar fixtures may process and emit other radiantenergy spectra, for discussion here we will assume these “lighting”fixtures process and emit light in the visible part of the spectrum.These first three examples are similar to each other, and the commonaspects are described first. Each fixture 250 (250 a to 250 c in FIGS.15A to 15C, respectively) includes an optical integrating cavity andLEDs similar to those in the example of FIG. 1 and like referencenumerals are used to identify the corresponding components. A powersource and control circuit similar to those used in the earlier examplesprovide the drive currents for the LEDs, and in view of the similarity,the power source and control circuit are omitted from these figures, tosimplify the illustrations.

In the examples of FIGS. 15 a to 15C, each light fixture 250 a to 250 cincludes an optical integrating cavity 11, formed by a dome 11 and acover plate 15. The surfaces of the dome 13 and cover 15 forming theinterior surface(s) of the cavity 11 are diffusely reflective. One ormore apertures 17, in these examples formed through the plate 15,provide a light passage for transmission of reflected and integratedlight outward from the cavity 11. Materials, positions, orientations andpossible shapes for the elements 11 to 17 have been discussed above.

As in the earlier examples, each fixture 250 a to 250 c includes anumber of LEDs 19 emitting light of different wavelengths into thecavity 11, as in the example of FIG. 1. A number of the LEDs will beactive, from initial start-up, whereas others may initially be inactive‘sleepers,’ as also discussed above. The possible combinations andpositions of the LEDs 19 have been discussed in detail above, inrelation to the earlier examples. Again, the LEDs 19 emit light ofmultiple colors into the interior of the optical integrating cavity.Control of the amplitudes of the drive currents applied to the LEDs 19controls the amount of each light color supplied into the cavity 11. Thecavity 11 integrates the various amounts of light of the differentcolors into a combined light for emission through the aperture 17.

The three examples (FIGS. 15A to 15C) differ as to the processingelement coupled to the aperture that processes the integrated colorlight output coming out of the aperture 17. In the example of FIG. 15A,instead of a deflector as in FIG. 1, the fixture 250 a includes a lens251 a in or covering the aperture 17. The lens may take any convenientform, for focusing or diffusing the emitted combined light, as desiredfor a particular application of the fixture 250 a. The lens 251 a may beclear or translucent.

In the example of FIG. 15B, the fixture 250 b includes a curvedtransmissive diffuser 251 a covering the aperture 17. The diffuser maytake any convenient form, for example, a white or clear dome of plasticor glass. Alternatively, the dome may be formed of a prismatic material.In addition to covering the aperture, the element 251 b diffuses theemitted combined light, as desired for a particular application of thefixture 250 b. The dome shaped diffuser may cover just the aperture, asshown at 251 b, or it may cover the backs of the LEDs 19 as well.

In the example of FIG. 15C, a holographic diffraction plate or grading251 c serves as the optical output processing element in the fixture 250c. The holographic grating is another form of diffuser. The holographicdiffuser 251 c is located in the aperture 17 or attached to the plate 15to cover the aperture 17. A holographic diffuser provides more precisecontrol over the diffuse area of illumination and increases transmissionefficiency. Holographic diffusers and/or holographic films are availablefrom a number of manufacturers, including Edmund Industrial Optics ofBarrington, N.J.

Those skilled in the art will recognize that still other lightprocessing elements may be used in place of the output lens 251 a, thediffuser 251 b and the holographic diffuser 251 c, to process or guidethe integrated light output. For example, a fiber optic bundle may beused to channel the light to a desired point, for example representing apixel on a large display screen (e.g. a jumbo tron).

The exemplary systems discussed herein may have any size desirable forany particular application. A system may be relatively large, forlighting a room or providing spot or flood lighting. The system also maybe relatively small, for example, to provide a small pinpoint of light,for an indicator or the like. The system 250 a, with or even without thelens, is particularly amenable to miniaturization. For example, insteadof a plate to support the LEDs, the LEDs could be manufactured on asingle chip. If it was not convenient to provide the aperture throughthe chip, the aperture could be formed through the reflective dome.

FIG. 16 illustrates another example of a “lighting” system 260 with anoptical integrating cavity LED light fixture, having yet other elementsto optically process the combined color light output. The system 260includes an optical integrating cavity and LEDs similar to those in theexamples of FIGS. 1 and 15, and like reference numerals are used toidentify the corresponding components.

In the example of FIG. 16, the light fixture includes an opticalintegrating cavity 11, formed by a dome 11 and a cover plate 15. Thesurfaces of the dome 13 and cover 15 forming the interior surface(s) ofthe cavity 11 are diffusely reflective. One or more apertures 17, inthis example formed through the plate 15, provide a light passage fortransmission of reflected and integrated light outward from the cavity11. Materials, possible shapes, positions and orientations for theelements 11 to 17 have been discussed above. As in the earlier examples,the system 260 includes a number of LEDs 19 emitting light of differentwavelengths into the cavity 11. The possible combinations and positionsof the LEDs 19 have been discussed in detail above, in relation to theearlier examples.

The LEDs 19 emit light of multiple colors into the interior of theoptical integrating cavity 11. In this example, the light colors are inthe visible portion of the radiant energy spectrum. Control of theamplitudes of the drive currents applied to the LEDs 19 controls theamount of each light color supplied into the cavity 11. A number of theLEDs will be active, from initial start-up, whereas others may initiallybe inactive ‘sleepers,’ as discussed above. The cavity 11 integrates thevarious amounts of light of the different colors into a combined lightof a desired color temperature for emission through the aperture 17.

The system 260 also includes a control circuit 262 coupled to the LEDs19 for establishing output intensity of radiant energy of each of theLED sources. The control circuit 262 typically includes a power supplycircuit coupled to a source, shown as an AC power source 264, althoughthe power source 264 may be a DC power source. In either case, thecircuit 262 may be adapted to process the voltage from the availablesource to produce the drive currents necessary for the LEDs 19. Thecontrol circuit 262 includes an appropriate number of LED drivercircuits, as discussed above relative to FIGS. 10 and 11, forcontrolling the power applied to each of the individual LEDs 19 and thusthe intensity of radiant energy supplied to the cavity 11 for eachdifferent type/color of light. Control of the intensity of emission ofeach of the LED sources sets a spectral characteristic of the combinedradiant energy emitted through the aperture 17 of the opticalintegrating cavity 11, in this case, the color characteristic(s) of thevisible light output.

The control circuit 262 may respond to a number of different controlinput signals, for example, to one or more user inputs as shown by thearrow in FIG. 16. Feedback may also be provided by a temperature sensor(not shown in this example) or one or more color sensors 266. The colorsensor(s) 266 may be located in the cavity or in the element or elementsfor processing light emitted through the aperture 17. However, in manycases, the plate 15 and/or dome 13 may pass some of the integrated lightfrom the cavity, in which case, it is actually sufficient to place thecolor light sensor(s) 266 adjacent any such transmissive point on theouter wall that forms the cavity. In the example, the sensor 266 isshown attached to the plate 15. Details of the control feedback havebeen discussed earlier, with regard to the circuitry in FIG. 10.

The example of FIG. 16 utilizes a different arrangement for directingand processing the light after emission from the cavity 11 through theaperture 17. This system 260 utilizes a collimator 253, an adjustableiris 255 and an adjustable focus lens system 259.

The collimator 253 may have a variety of different shapes, depending onthe desired application and the attendant shape of the aperture 17. Forease of discussion here, it is assumed that the elements shown arecircular, including the aperture 17. Hence, in the example, thecollimator 253 comprises a substantially cylindrical tube, having acircular opening at a proximal end coupled to the aperture 17 of theoptical integrating cavity 11. The system 260 emits light toward adesired field of illumination via the circular opening at the distal endof the collimator 253.

The interior surface of the collimator 253 is reflective. The reflectiveinner surface may be diffusely reflective or quasi-specular. Typically,in this embodiment, the interior surface of the deflector/collimatorelement 253 is specular. The tube forming the collimator 253 alsosupports a series of elements for optically processing the collimatedand integrated light. Those skilled in the art will be familiar with thetypes of processing elements that may be used, but for purposes ofunderstanding, it may be helpful to consider two specific types of suchelements.

First, the tube forming the collimator 253 supports a variable iris. Theiris 257 represents a secondary aperture, which effectively limits theoutput opening and thus the intensity of light that may be output by thesystem 260. Although shown in the collimator tube, the iris may bemounted in or serve as the aperture 17. A circuit 257 controls the sizeor adjustment of the opening of the iris 255. In practice, the useractivates the LED control circuit (see e.g. 21 in FIG. 1) to set thecolor balance or temperature of the output light, that is to say, sothat the system 260 outputs light of a desired color. The overallintensity of the output light is then controlled through the circuit 257and the iris 255. Opening the iris 255 wider provides higher outputintensity, whereas reducing the iris opening size decreases intensity ofthe light output.

In the system 260, the tube forming the collimator 253 also supports oneor more lens elements of the adjustable focusing system 259, shown byway of example as two lenses 261 and 263. Spacing between the lensesand/or other parameters of the lens system 259 are adjusted by amechanism 265, in response to a signal from a focus control circuit 267.The elements 261 to 267 of the system 259 are shown here by way ofexample, to represent a broad class of elements that may be used tovariably focus the emitted light in response to a control signal ordigital control information or the like. If the system 260 serves as aspot light, adjustment of the lens system 259 effectively controls thesize of the spot on the target object or subject that the systemilluminates. Those skilled in the art will recognize that other opticalprocessing elements may be provided, such as a mask to control the shapeof the illumination spot or various shutter arrangements for beamshaping.

Although shown as separate control circuits 257 and 267, the functionsof these circuits may be integrated together with each other orintegrated into the circuit 262 that controls the operation of the LEDs19. For example, the system might use a single microprocessor or similarprogrammable microcontroller, which would run control programs for theLED drive currents, the iris control and the focus control.

The optical integrating cavity 11 and the LEDs 19 produce light of aprecisely controlled composite color. As noted, control of the LEDcurrents controls the amount of each color of light integrated into theoutput and thus the output light color. Control of the opening providedby the iris 255 then controls the intensity of the integrated lightoutput of the system 260. Control of the focusing by the system 259enables control of the breadth of the light emissions and thus thespread of the area or region to be illuminated by the system 260. Otherelements may be provided to control beam shape. Professional productionlighting applications for such a system include theater or studiolighting, for example, where it is desirable to control the color,intensity and the size of a spotlight beam. By connecting the LEDcontrol circuit 257, the iris control circuit 257 and the focus controlcircuit 267 to a network similar to that in FIG. 12, it becomes possibleto control color, intensity and spot size from a remote networkterminal, for example, at an engineer's station in the studio ortheater.

The discussion of the examples above has mainly referenced illuminancetype lighting applications, for example to illuminate rooms or providespot lighting in a theater or studio. Only brief mention has been givenso far, of other applications. Those skilled in the art will recognize,however, that the principles discussed herein may also find wide use inother applications, particularly in luminance applications, such asvarious kinds of signal lighting.

FIG. 17 is a cross-sectional view of another example of an opticalcavity LED type fixture. Although this design may be used forillumination, for purposes of discussion here, we will concentrate onapplication for luminance purposes. The fixture 300 includes an opticalcavity 311 having a diffusely reflective inner surface, as in theearlier examples. In this fixture, the cavity 311 has a substantiallyrectangular cross-section. FIG. 18 is an isometric view of a portion ofa fixture having the cross-section of FIG. 17, showing several of thecomponents formed as a single extrusion of the desired cross section.FIGS. 19 and 20 then show use of such a fixture arranged so as toconstruct lighted letters.

The fixture 300 preferably includes several initially-active LEDs andseveral sleeper LEDs, generally shown at 319, similar to those in theearlier examples. The LEDs emit controlled amounts of multiple colors oflight into the optical integrating cavity 311 formed by the innersurfaces of a rectangular member 313. A power source and control circuitsimilar to those used in the earlier examples provide the drive currentsfor the LEDs 319, and in view of the similarity, the power source andcontrol circuit are omitted from FIG. 17, to simplify the illustration.One or more apertures 317, of the shape desired to facilitate theparticular luminance application, provide light passage for transmissionof reflected and integrated light outward from the cavity 311. Materialsfor construction of the cavity and the types of LEDs that may be usedare similar to those discussed relative to the earlier illuminationexamples, although the number and intensities of the LEDs may bedifferent, to achieve the output parameters desired for the particularluminance application.

The fixture 300 in this example (FIG. 17) includes a deflector 325 tofurther process and direct the light emitted from the aperture 317 ofthe optical integrating cavity 311. The deflector 325 has a reflectiveinterior surface 329 and expands outward laterally from the aperture, asit extends away from the cavity toward the region to be illuminated. Ina circular implementation, the deflector 325 would be conical. However,in the example of FIG. 18, the deflector is formed by two opposingpanels 325 a and 325 b of the extruded body. The surfaces 329 a and 329b of the panels are reflective. As in the earlier examples, all orportions of the deflector surfaces may be diffusely reflective,quasi-specular or specular. For some examples, it may be desirable tohave one panel surface 329 a diffusely reflective and have specularreflectivity on the other panel surface 329 b.

As shown in FIG. 17, a small opening at a proximal end of the deflector325 is coupled to the aperture 317 of the optical integrating cavity311. The deflector 325 has a larger opening at a distal end thereof. Theangle of the interior surface 329 and size of the distal opening of thedeflector 325 define an angular field of radiant energy emission fromthe apparatus 300. The large opening of the deflector 325 is coveredwith a grating, a plate or the exemplary lens 331 (which is omitted fromFIG. 18, for convenience). The lens 331 may be clear or translucent toprovide a diffuse transmissive processing of the light passing out ofthe large opening. Prismatic materials, such as a sheet of microprismplastic or glass also may be used.

The overall shape of the fixture 300 may be chosen to provide a desiredluminous shape, for example, in the shape of any selected number,character, letter, or other symbol. FIG. 19, for example, shows a viewof such a fixture, as if looking back from the area receiving the light,with the lens removed from the output opening of the deflector. In thisexample, the aperture 317 ₁ and the output opening of the deflector 325₁ are both rectangular, although they may have somewhat rounded corners.Alternatively, the deflector may be somewhat oval in shape. To theobserver, the fixture will appear as a tall rectangular light. If thelong dimension of the rectangular shape is extended or elongatedsufficiently, the lighted fixture might appear as a lighted letter I.The shapes of the cavity and the aperture may vary, for example, to haverounded ends, and the deflector may be contoured to match the aperture,for example, to provide softer or sharper edges and/or to create adesired font style for the letter.

FIG. 20 shows a view of another example such a fixture, again as iflooking back from the area receiving the light with the lens removedfrom the output opening of the deflector. In this example, the aperture317 ₂ and the output opening of the deflector 325 ₂ are both L-shaped.When lighted, the observer will perceive the fixture as a lighted letterL. Of course, the shapes of the aperture and deflector openings may varysomewhat, for example, by using curves or rounded corners, so the letterapproximates the shape for a different type font.

The extruded body construction illustrated in FIG. 18 may be curved orbent for use in different letters. By combining several versions of thefixture 300, shaped to represent different letters, it becomes possibleto spell out words and phrases. Control of the amplitudes of the drivecurrents applied to the LEDs 319 of each fixture controls the amount ofeach light color supplied into the respective optical integrating cavityand thus the combined light output color of each number, character,letter, or other symbol.

FIGS. 21 and 22 show another fixture, but here adapted for use as a“wall-washer” illuminant lighting fixture. The fixture 330 includes anoptical integrating cavity 331 having a diffusely reflective innersurface, as in the earlier examples. In this fixture, the cavity 331again has a substantially rectangular cross-section. FIG. 22 is anisometric view of a section of the fixture, showing several of thecomponents formed as a single extrusion of the desired cross section,but without any end-caps.

As shown in these figures, the fixture 330 includes severalinitially-active LEDs and several sleeper LEDs, generally shown at 339,similar to those in the earlier examples. The LEDs emit controlledamounts of multiple colors of light into the optical integrating cavity341 formed by the inner surfaces of a rectangular member 333. A powersource and control circuit similar to those used in the earlier examplesprovide the drive currents for the LEDs 339, and in view of thesimilarity, the power source and control circuit are omitted from FIG.21, to simplify the illustration. One or more apertures 337, of theshape desired to facilitate the particular lighting application, providelight passage for transmission of reflected and integrated light outwardfrom the cavity 341. Materials for construction of the cavity and thetypes of LEDs that may be used are similar to those discussed relativeto the earlier illumination examples, although the number andintensities of the LEDs may be different, to achieve the outputparameters desired for the particular wall-washer application.

The fixture 330 in this example (FIG. 21) includes a deflector tofurther process and direct the light emitted from the aperture 337 ofthe optical integrating cavity 341, in this case toward a wall, productor other subject somewhat to the left of and above the fixture 330. Thedeflector is formed by two opposing panels 345 a and 345 b of theextruded body of the fixture. The panel 345 a is relatively flat andangled somewhat to the left, in the illustrated orientation. Assuming avertical orientation of the fixture as shown in FIG. 21, the panel 345 bextends vertically upward from the edge of the aperture 337 and is bentback at about 90°. The shapes and angles of the panels 345 a and 345 bare chosen to direct the light to a particular area of a wall or productdisplay that is to be illuminated, and may vary from application toapplication.

Each panel 345 a, 345 b has a reflective interior surface 349 a, 349 b.As in the earlier examples, all or portions of the deflector surfacesmay be diffusely reflective, quasi-specular or specular. In the wallwasher example, the deflector panel surface 349 b is diffuselyreflective, and the deflector panel surface 349 a has a specularreflectivity, to optimize distribution of emitted light over the desiredarea illuminated by the fixture 330.

The output opening of the deflector 345 may be covered with a grating, aplate or lens, in a manner similar to the example of FIG. 17, althoughin the illustrated wall washer example, such an element is omitted.

FIG. 23 is a cross sectional view of another example of a wall washertype fixture 350. The fixture 350 includes an optical integrating cavity351 having a diffusely reflective inner surface, as in the earlierexamples. In this fixture, the cavity 351 again has a substantiallyrectangular cross-section. As shown, the fixture 350 includes at leastone white light source, represented by the white LED 355. The fixturealso includes several LEDs 359 of the various primary colors, typicallyred (R), green (G) and blue (B, not visible in this cross-sectionalview). The LEDs 359 include both initially-active LEDs and sleeper LEDs,and the LEDs 359 are similar to those in the earlier examples. Again,the LEDs emit controlled amounts of multiple colors of light into theoptical integrating cavity 351 formed by the inner surfaces of arectangular member 353. A power source and control circuit similar tothose used in the earlier examples provide the drive currents for theLEDs 359, and in this example, that same circuit controls the drivecurrent applied to the white LED 355. In view of the similarity, thepower source and control circuit are omitted from FIG. 23, to simplifythe illustration.

One or more apertures 357, of the shape desired to facilitate theparticular lighting application, provide light passage for transmissionof reflected and integrated light outward from the cavity 351. Theaperture may be laterally centered, as in the earlier examples; however,in this example, the aperture is off-center to facilitate alight-through to the left (in the illustrated orientation). Materialsfor construction of the cavity and the types of LEDs that may be usedare similar to those discussed relative to the earlier illuminationexamples.

Here, it is assumed that the fixture 350 is intended to principallyprovide white light, for example, to illuminate a wall or product to theleft and somewhat above the fixture. The presence of the white lightsource 355 increases the intensity of white light that the fixtureproduces. The control of the outputs of the primary color LEDs 359allows the operator to correct for any variations of the white lightfrom the source 355 from normal white light and/or to adjust the colorbalance/temperature of the light output. For example, if the white lightsource 355 is an LED as shown, the white light it provides tends to berather blue. The intensities of light output from the LEDs 359 can beadjusted to compensate for this blueness, for example, to provide alight output approximating sunlight or light from a common incandescentsource, as or when desired.

As another example of operation, the fixture 350 may be used toilluminate products, e.g. as displayed in a store or the like, althoughit may be rotated or inverted for such a use. Different products maypresent a better impression if illuminated by white light having adifferent balance. For example, fresh bananas may be more attractive toa potential customer when illuminated by light having more yellow tones.Soda sold in red cans, however, may be more attractive to a potentialcustomer when illuminated by light having more red tones. For eachproduct, the user can adjust the intensities of the light outputs fromthe LEDs 359 and/or 355 to produce light that appears substantiallywhite if observed directly by a human/customer but provides the desiredhighlighting tones and thereby optimizes lighting of the particularproduct that is on display.

The fixture 350 may have any desired output processing element(s), asdiscussed above with regard to various earlier examples. In theillustrated wall washer embodiment (FIG. 23), the fixture 350 includes adeflector to further process and direct the light emitted from theaperture 357 of the optical integrating cavity 351, in this case towarda wall or product somewhat to the left of and above the fixture 350. Thedeflector is formed by two opposing panels 365 a and 365 b havingreflective inner surfaces 365 a and 365 b. Although other shapes may beused to direct the light output to the desired area or region, theillustration shows the panel 365 a, 365 b as relatively flat panels setat somewhat different angle extending to the left, in the illustratedorientation. Of course, as for all the examples, the fixture may beturned at any desired angle or orientation to direct the light to aparticular region or object to be illuminated by the fixture, in a givenapplication.

As noted, each panel 365 a, 365 b has a reflective interior surface 369a, 369 b. As in the earlier examples, all or portions of the deflectorsurfaces may be diffusely reflective, quasi-specular or specular. In thewall washer example, the deflector panel surface 369 b is diffuselyreflective, and the deflector panel surface 369 a has a specularreflectivity, to optimize distribution of emitted light over the desiredarea of the wall illuminated by the fixture 350. The output opening ofthe deflector 365 may be covered with a grating, a plate or lens, in amanner similar to the example of FIG. 17, although in the illustratedwall washer example, such an element is omitted.

FIG. 24 is a cross-sectional view of another example of an opticalintegrating cavity type light fixture 370. This example uses a deflectorand lens to optically process the light output, and like the example ofFIG. 23 the fixture 370 includes LEDs to produce various colors of lightin combination with a white light source. The fixture 370 includes anoptical integrating cavity 371, formed by a dome and a cover plate,although other structures may be used to form the cavity. The surfacesof the dome and cover forming the interior surface(s) of the cavity 371are diffusely reflective. One or more apertures 377, in this exampleformed through the cover plate, provide a light passage for transmissionof reflected and integrated light outward from the cavity 371.Materials, sizes, orientation, positions and possible shapes for theelements forming the cavity and the types/numbers of LEDs have beendiscussed above.

As shown, the fixture 370 includes at least one white light source.Although the white light source could comprise one or more LEDs, as inthe previous example (FIG. 23), in this embodiment, the white lightsource comprises a lamp 375. The lamp may be any convenient form oflight bulb, such as an incandescent or fluorescent light bulb; and theremay be one, two or more bulbs to produce a desired amount of whitelight. A preferred example of the lamp 375 is a quartz halogen lightbulb. The fixture also includes several LEDs 379 of the various primarycolors, typically red (R), green (G) and blue (B, not visible in thiscross-sectional view), although additional colors may be provided orother color LEDs may be substituted for the RGB LEDs. Some LEDs will beactive from initial operation. Other LEDs may be held in reserve assleepers. The LEDs 379 are similar to those in the earlier examples, foremitting controlled amounts of multiple colors of light into the opticalintegrating cavity 371.

A power source and control circuit similar to those used in the earlierexamples provide the drive currents for the LEDs 359. In view of thesimilarity, the power source and control circuit for the LEDs areomitted from FIG. 24, to simplify the illustration. The lamp 375 may becontrolled by the same or similar circuitry, or the lamp may have afixed power source.

The white light source 375 may be positioned at a point that is notdirectly visible through the aperture 377 similar to the positions ofthe LEDs 379. However, for applications requiring relatively high whitelight output intensity, it may be preferable to position the white lightsource 375 to emit a substantial portion of its light output directlythrough the aperture 377.

The fixture 370 may incorporate any of the further optical processingelements discussed above. For example, the fixture may include avariable iris and variable focus system, as in the embodiment of FIG.16. In the illustrated version, however, the fixture 370 includes adeflector 385 to further process and direct the light emitted from theaperture 377 of the optical integrating cavity 371. The deflector 385has a reflective interior surface 389 and expands outward laterally fromthe aperture, as it extends away from the cavity toward the region to beilluminated. In a circular implementation, the deflector 385 would beconical. Of course, for applications using other fixture shapes, thedeflector may be formed by two or more panels of desired sizes andshapes. The interior surface 389 of the deflector 385 is reflective. Asin the earlier examples, all or portions of the reflective deflectorsurface(s) may be diffusely reflective, quasi-specular, specular orcombinations thereof.

As shown in FIG. 24, a small opening at a proximal end of the deflector385 is coupled to the aperture 377 of the optical integrating cavity311. The deflector 385 has a larger opening at a distal end thereof. Theangle of the interior surface 389 and size of the distal opening of thedeflector 385 define an angular field of radiant energy emission fromthe apparatus 370.

The large opening of the deflector 385 is covered with a grating, aplate or the exemplary lens 387. The lens 387 may be clear ortranslucent to provide a diffuse transmissive processing of the lightpassing out of the large opening. Prismatic materials, such as a sheetof microprism plastic or glass also may be used. In applications where aperson may look directly at the fixture 370 from the illuminated region,it is preferable to use a translucent material for the lens 387, toshield the observer from directly viewing the lamp 375.

The fixture 370 thus includes a deflector 385 and lens 387, for opticalprocessing of the integrated light emerging from the cavity 371 via theaperture 377. Of course, other optical processing elements may be usedin place of or in combination with the deflector 385 and/or the lens387, such as those discussed above relative to FIGS. 15A to 15C and 16.

In the fixture of FIG. 24, the lamp 375 provides substantially whitelight of relatively high intensity. The integration of the light fromthe LEDs 379 in the cavity 375 supplements the light from the lamp 375with additional colors, and the amounts of the different colors of lightfrom the LEDs can be precisely controlled. Control of the light addedfrom the LEDs can provide color correction and/or adjustment, asdiscussed above relative to the embodiment of FIG. 23.

As shown by the discussion above, each of the various radiant energyemission systems with multiple color sources and an optical cavity tocombine the energy from the sources provides a highly effective means tocontrol the color produced by one or more fixtures. The output colorcharacteristics are controlled simply by controlling the intensity ofeach of the sources supplying radiant energy to the chamber.

Settings for a desirable color are easily reused or transferred from onesystem/fixture to another. If color/temperature/balance offered byparticular settings are found desirable, e.g. to light a particularproduct on display or to illuminate a particular person in a studio ortheater, it is a simple matter to record those settings and apply themat a later time. Similarly, such settings may be readily applied toanother system or fixture, e.g. if the product is displayed at anotherlocation or if the person is appearing in a different studio or theater.It may be helpful to consider the product and person lighting examplesin somewhat more detail.

For the product, assume that a company will offer a new soft drink in acan having a substantial amount of red product markings. The company cantest the product under lighting using one or more fixtures as describedherein, to determine the optimum color to achieve a desired brilliantdisplay. In a typical case, the light will generally be white to theobserver. In the case of the red product container, the white light willhave a relatively high level of red, to make the red markings seem toglow when the product is viewed by the casual observer/customer. Whenthe company determines the appropriate settings for the new product, itcan distribute those settings to the stores that will display and sellthe product. The stores will use other fixtures of any type disclosedherein. The fixtures in the stores need not be of the exact same typethat the company used during product testing. Each store uses thesettings received from the company to establish the spectralcharacteristic(s) of the lighting applied to the product by the store'sfixture(s), in our example, so that each product display provides thedesired brilliant red illumination of the company's new soft drinkproduct.

Consider now a studio lighting example for an actor or newscaster. Theperson is tested under lighting using one or more fixtures as describedherein, to determine the optimum color to achieve desired appearance invideo or film photography of the individual. Again, the light willgenerally be white to the observer, but each person will appear betterat somewhat different temperature or color balance levels. One personmight appear more healthy and natural under warmer light, whereasanother might appear better under bluer/colder white light. Aftertesting to determine the person's best light color settings, thesettings are recorded. Each time the person appears under any lightingusing the systems disclosed herein, in the same or a different studio,the technicians operating the lights can use the same settings tocontrol the lighting and light the person with light of exactly the samespectral characteristic(s). Similar processes may be used to define aplurality of desirable lighting conditions for the actor or newscaster,for example, for illumination for different moods or different purposesof the individual's performances.

The methods for defining and transferring set conditions, e.g. forproduct lighting or personal lighting, can utilize manual recordings ofsettings and input of the settings to the different lighting systems.However, it is preferred to utilize digital control, in systems such asdescribed above relative to FIGS. 10 and 12. Once input to a givenlighting system, a particular set of parameters for a product orindividual become another ‘preset’ lighting recipe stored in digitalmemory, which can be quickly and easily recalled and used each time thatthe particular product or person is to be illuminated.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that they may be appliedin numerous applications, only some of which have been described herein.It is intended by the following claims to claim any and allmodifications and variations that fall within the true scope of thepresent concepts.

1. An apparatus for emitting radiant energy, comprising: a first ofsource of radiant energy of a first wavelength; a second source ofradiant energy of a second wavelength, the second wavelength beingdifferent from the first wavelength; an optical cavity having adiffusely reflective interior surface for receiving and combiningradiant energy of the first and second wavelengths from the sources ofradiant energy, and having an aperture for allowing emission of combinedradiant energy containing both radiant energy of the first wavelengthand radiant energy of the second wavelength; and an optical processingelement coupled to the aperture of the optical cavity.
 2. The apparatusof claim 1, wherein the optical processing element comprises a deflectorhaving a reflective inner surface coupled to the aperture to deflect atleast some of the combined radiant energy.
 3. The apparatus of claim 2,wherein at least a substantial portion of the reflective inner surfaceof the deflector exhibits a diffuse reflective characteristic withrespect to the combined radiant energy.
 4. The apparatus of claim 2,wherein: a first portion of the reflective inner surface of thedeflector exhibits a diffuse reflective characteristic with respect tothe combined radiant energy; and a second portion of the reflectiveinner surface of the deflector exhibits a specular reflectivecharacteristic with respect to the combined radiant energy.
 5. Theapparatus of claim 1, wherein the optical processing element comprises avariable opening iris.
 6. The apparatus of claim 1, wherein the opticalprocessing element comprises a variable focusing lens system.
 7. Theapparatus of claim 6, further comprising a variable opening iris locatedbetween the cavity and the variable focusing lens system.
 8. Theapparatus of claim 1, wherein the optical processing element comprises acollimator coupled to the aperture of the optical cavity.
 9. Theapparatus of claim 1, wherein the optical processing element comprises atransmissive diffuser coupled to the aperture of the optical cavity. 10.The apparatus of claim 9, wherein the transmissive diffuser comprises alens.
 11. The apparatus of claim 9, wherein the transmissive diffusercomprises a curved transmissive cover over the aperture of the opticalcavity.
 12. The apparatus of claim 9, wherein the transmissive diffusercomprises a holographic diffuser.
 13. The apparatus of claim 1, furthercomprising control circuitry coupled to the first and second sources forestablishing intensity of radiant energy from each of the sources, so asto set a spectral characteristic of the combined radiant energy emittedthrough the aperture and the optical processing element.
 14. Theapparatus of claim 1, wherein: the first source comprises one or morelight emitting diodes for emitting light of a first visible color; andthe second source comprises one or more light emitting diodes foremitting light of a second visible color, wherein the second color isdifferent from the first color.
 15. The apparatus of claim 14, wherein:the one or more first color light emitting diodes comprise an initiallyactive light emitting diode for emitting light of the first color and aninitially inactive light emitting diode for emitting light of the firstcolor on an as needed basis; and the one or more second color lightemitting diodes comprises an initially active light emitting diode foremitting light of the second color and an initially inactive lightemitting diode for emitting light of the second color on an as neededbasis.
 16. The apparatus of claim 15, further comprising a third sourcefor supplying radiant energy into the optical cavity for combinationwith the radiant energy of the first and second wavelengths, wherein thethird source produces substantially white light.
 17. The apparatus ofclaim 16, wherein third source comprises one or more white lightemitting diodes.
 18. The apparatus of claim 16, wherein third sourcecomprises one or more incandescent or fluorescent light bulbs.
 19. Theapparatus of claim 1, further comprising a third source for supplyingradiant energy of a third wavelength into the optical cavity forcombination with the radiant energy of the first and second wavelengths,the third wavelength being different from the first wavelength and fromthe second wavelength.
 20. The apparatus of claim 19, wherein: the firstsource comprises one or more light emitting diodes for emitting light ofa first visible color; the second source comprises one or more lightemitting diodes for emitting light of a second visible color, whereinthe second color is different from the first color; and the third sourcecomprises one or more light emitting diodes for emitting light of athird visible color, wherein the third color is different from the firstcolor and from the second color.
 21. The apparatus of claim 20, whereinthe first, second and third colors are red, green and blue,respectively.
 22. A system comprising: a plurality of apparatuses foremitting radiant energy, each as specified in claim 1; and a mastercontroller coupled to control each of the apparatuses, for providing acommon control of all radiant energy emissions by the apparatuses.
 23. Alighting system, for providing variable color lighting for studio ortheater applications, the lighting system comprising: a first of sourceof light of a first wavelength; a second source of light of secondwavelength, the second wavelength being different from the firstwavelength; an optical cavity having a diffusely reflective interiorsurface for receiving and combining light of the first and secondwavelengths from the sources, and having an aperture for allowingemission of combined light of both the first wavelength and the secondwavelength; a variable opening iris optically coupled to the aperture ofthe optical cavity, for controlling an amount of the combined lightemitted toward a subject to be illuminated; and control circuitrycoupled to the first and second sources for establishing intensity oflight from the sources, so as to set a spectral characteristic of thecombined light directed toward the subject to be illuminated in thestudio or theater.
 24. The lighting system of claim 23, furthercomprising a variable focusing lens system, for adjustably focusing thecombined light emitted through the iris toward the subject to beilluminated.
 25. The lighting system of claim 23, wherein: the firstsource comprises one or more light emitting diodes for emitting light ofa first visible color; and the second source comprises one or more lightemitting diodes for emitting light of a second visible color, whereinthe second color is different from the first color.
 26. The lightingsystem of claim 25, wherein the control circuitry comprises: a colorsensor responsive to the combined light; and logic circuitry responsiveto color detected by the sensor to control output intensity of the oneor more first color light emitting diodes and intensity of the one ormore second color light emitting diodes, so as to provide a desiredcolor distribution in the combined light directed toward the subject tobe illuminated in the studio or theater.
 27. The lighting system ofclaim 25, wherein: the one or more first color light emitting diodescomprise an initially active light emitting diode for emitting light ofthe first color and an initially inactive diode for emitting light ofthe first color on an as needed basis; and the one ore more second colorlight emitting diodes comprises an initially active light emitting diodefor emitting light of the second color and an initially inactive diodefor emitting light of the second color on an as needed basis.
 28. Thelighting system of claim 27, wherein the control circuitry comprises: acolor sensor responsive to the combined light; and logic circuitryresponsive to color detected by the sensor to control output intensityof the one or more first color light emitting diodes and intensity ofthe one or more second color light emitting diodes, so as to provide adesired color distribution in the combined light directed toward thesubject to be illuminated in the studio or theater, and wherein thelogic circuitry is responsive to the detected color to selectivelyactivate the inactive light emitting diodes, as needed to maintain thedesired color distribution in the integrated radiant energy.
 29. Thelighting system of claim 25, further comprising one or more lightemitting diodes for supplying substantially white light into the opticalcavity for combination with the light of the first and secondwavelengths.
 30. The lighting system of claim 23, further comprising athird source for supplying substantially white light into the opticalcavity for combination with the light of the first and secondwavelengths.
 31. The lighting system of claim 30, wherein the thirdsource comprises one or more incandescent or fluorescent light bulbs.32. A lighting network comprising: a plurality of lighting systems, eachas specified in claim 23; and a master controller communicativelynetworked to the control circuitry of each of the lighting systems, forproviding a common control of all light emissions by the lightingsystems.
 33. A lighting fixture, for a luminous lighting application,the fixture comprising: a first of source of light of a firstwavelength; a second source of light of second wavelength, the secondwavelength being different from the first wavelength; an optical cavityhaving a diffusely reflective interior surface for receiving andcombining light of the first and second wavelengths from the sources,and having an aperture for allowing emission of combined light of boththe first wavelength and the second wavelength; and at least one opticalprocessing element coupled to the aperture of the optical cavity, forprocessing the combined light in a manner facilitating the luminouslighting application.
 34. The lighting fixture of claim 33, wherein theat least one optical processing element comprises a reflective deflectorshaped like a number, character, letter, or symbol, having a proximalopening coupled to the aperture of the optical cavity.
 35. The lightingfixture of claim 34, further comprising a transmissive light diffusingmember across a distal opening of the deflector.
 36. The lightingfixture of claim 33, wherein the aperture is shaped like a number,character, letter, or symbol.
 37. The lighting fixture of claim 33, incombination with control circuitry coupled to the first and secondsources for establishing output intensity of light output of each of thesources, so as to set a spectral characteristic of the combined lightemitted by the fixture.
 38. A method of illuminating a subject,comprising: generating a variable amount of light of a first wavelengthand a variable amount of light of a second wavelength, wherein thesecond wavelength is different from the first wavelength; opticallycombining the light of the first wavelength with the light of the secondwavelength; illuminating the subject with the combined light; adjustingthe amount of the light of the first wavelength or the amount of thelight of the second wavelength, to achieve a color characteristic of adesired illumination of the subject with the combined light; recordingthe amount of the light of the first wavelength and the amount of thelight of the second wavelength contained in the combined light used toachieve the desired illumination of the subject; setting a lightingsystem to generate the recorded amount of the light of the firstwavelength and to generate the recorded amount of the light of thesecond wavelength; operating the lighting system to generate the setrecorded amounts of light of the first and second wavelengths; opticallycombining the light of the first and second wavelengths generated by thelighting system to produce a combined light output corresponding to thedesired illumination; and irradiating the subject with the combinedlight output from the lighting system, to achieve the desiredillumination of the subject using the lighting system.
 39. The method ofclaim 38, wherein the subject illuminated comprises one or more examplesof a particular product.
 40. The method of claim 38, wherein the subjectilluminated is a particular person.
 41. The method of claim 38, whereinthe step of optically combining the light of the first and secondwavelengths generated by the lighting system, comprises: diffuselyreflecting the light of the first and second wavelengths generated bythe lighting system within a cavity; and emitting the light of the firstand second wavelengths through an aperture of the cavity as the combinedlight output.
 42. The method of claim 41, wherein the setting stepcomprises: setting an intensity of illumination of a source of the lightof the first wavelength for the lighting system to the recorded amountof the light of the first wavelength; and setting an intensity ofillumination of a source of the light of the second wavelength for thelighting system to the recorded amount of the light of the secondwavelength.
 43. A method of illuminating a subject with light of adesired color characteristic, comprising: setting a first amount forlight of a first wavelength; generating light of the first wavelengthfrom a first source, in a first intensity corresponding to the first setamount; setting a second amount for light of a second wavelength;generating light of the second wavelength from a second source, in asecond intensity corresponding to the second set amount; wherein thesecond wavelength is different from the first wavelength, and the firstand second set amounts correspond to the desired color characteristicfor the illumination of the subject; diffusely reflecting the generatedlight of the first and second wavelengths from the first and secondsources within a cavity, to produce combined light containing amounts oflight of the first and second wavelengths in proportion to the first andsecond set amounts; and emitting at least a portion of the combinedlight through an aperture of the cavity to illuminate the subject withlight of the desired color characteristic.
 44. The method of claim 43,wherein the subject illuminated comprises a particular product.
 45. Themethod of claim 43, wherein the subject illuminated is a particularperson.
 46. The method of claim 43, further comprising adjusting anopening of an iris optically coupled to the aperture, to control overallintensity of the combined light from the cavity illuminating thesubject.